From 89d754aa880163cc2e223aa4e5a7a7286413f1ce Mon Sep 17 00:00:00 2001
From: Jay Harris <jay.harris@outlook.co.nz>
Date: Tue, 1 Oct 2024 11:59:40 +1300
Subject: [PATCH 1/9] [Rounded Corners]: Fix shadows

---
 browser/ui/brave_browser.cc                   |  7 +++++
 browser/ui/brave_browser.h                    |  1 +
 .../views/frame/brave_browser_view_layout.cc  | 27 ++++++++++++-------
 .../views/frame/brave_contents_view_util.cc   |  7 +++--
 .../frame/vertical_tab_strip_region_view.cc   |  6 +++--
 .../ui/views/side_panel/brave_side_panel.cc   |  9 ++++++-
 6 files changed, 41 insertions(+), 16 deletions(-)

diff --git a/browser/ui/brave_browser.cc b/browser/ui/brave_browser.cc
index 350f9f2cef03..a3dbdfd94aa0 100644
--- a/browser/ui/brave_browser.cc
+++ b/browser/ui/brave_browser.cc
@@ -18,6 +18,7 @@
 #include "brave/browser/ui/brave_file_select_utils.h"
 #include "brave/browser/ui/tabs/brave_tab_prefs.h"
 #include "brave/browser/ui/tabs/features.h"
+#include "brave/browser/ui/views/frame/brave_contents_view_util.h"
 #include "brave/components/constants/pref_names.h"
 #include "chrome/browser/lifetime/browser_close_manager.h"
 #include "chrome/browser/profiles/profile.h"
@@ -57,6 +58,12 @@ bool BraveBrowser::ShouldUseBraveWebViewRoundedCorners(Browser* browser) {
          browser->is_type_normal();
 }
 
+int BraveBrowser::GetRoundedCornersWebViewMargin(Browser* browser) {
+  return ShouldUseBraveWebViewRoundedCorners(browser)
+             ? BraveContentsViewUtil::kMarginThickness
+             : 0;
+}
+
 BraveBrowser::BraveBrowser(const CreateParams& params) : Browser(params) {
 #if defined(TOOLKIT_VIEWS)
   if (!sidebar::CanUseSidebar(this)) {
diff --git a/browser/ui/brave_browser.h b/browser/ui/brave_browser.h
index f4e02d2b1e3d..15b70fe01ce2 100644
--- a/browser/ui/brave_browser.h
+++ b/browser/ui/brave_browser.h
@@ -32,6 +32,7 @@ class BraveBrowser : public Browser {
   BraveBrowser& operator=(const BraveBrowser&) = delete;
 
   static bool ShouldUseBraveWebViewRoundedCorners(Browser* browser);
+  static int GetRoundedCornersWebViewMargin(Browser* browser);
 
   // Browser overrides:
   void ScheduleUIUpdate(content::WebContents* source,
diff --git a/browser/ui/views/frame/brave_browser_view_layout.cc b/browser/ui/views/frame/brave_browser_view_layout.cc
index 3f790d22e2a8..2af91c9c9bee 100644
--- a/browser/ui/views/frame/brave_browser_view_layout.cc
+++ b/browser/ui/views/frame/brave_browser_view_layout.cc
@@ -67,8 +67,9 @@ void BraveBrowserViewLayout::Layout(views::View* host) {
 }
 
 void BraveBrowserViewLayout::LayoutVerticalTabs() {
-  if (!vertical_tab_strip_host_.get())
+  if (!vertical_tab_strip_host_.get()) {
     return;
+  }
 
   if (!tabs::utils::ShouldShowVerticalTabs(browser_view_->browser())) {
     vertical_tab_strip_host_->SetBorder(nullptr);
@@ -108,10 +109,11 @@ void BraveBrowserViewLayout::LayoutVerticalTabs() {
   insets = AdjustInsetsConsideringFrameBorder(insets);
 #endif
 
-  if (insets.IsEmpty())
+  if (insets.IsEmpty()) {
     vertical_tab_strip_host_->SetBorder(nullptr);
-  else
+  } else {
     vertical_tab_strip_host_->SetBorder(views::CreateEmptyBorder(insets));
+  }
 
   const auto width =
       vertical_tab_strip_host_->GetPreferredSize().width() + insets.width();
@@ -147,8 +149,9 @@ int BraveBrowserViewLayout::LayoutTabStripRegion(int top) {
 
 int BraveBrowserViewLayout::LayoutBookmarkAndInfoBars(int top,
                                                       int browser_view_y) {
-  if (!vertical_tab_strip_host_ || !ShouldPushBookmarkBarForVerticalTabs())
+  if (!vertical_tab_strip_host_ || !ShouldPushBookmarkBarForVerticalTabs()) {
     return BrowserViewLayout::LayoutBookmarkAndInfoBars(top, browser_view_y);
+  }
 
   auto new_rect = vertical_layout_rect_;
   new_rect.Inset(GetInsetsConsideringVerticalTabHost());
@@ -157,8 +160,9 @@ int BraveBrowserViewLayout::LayoutBookmarkAndInfoBars(int top,
 }
 
 int BraveBrowserViewLayout::LayoutInfoBar(int top) {
-  if (!vertical_tab_strip_host_)
+  if (!vertical_tab_strip_host_) {
     return BrowserViewLayout::LayoutInfoBar(top);
+  }
 
   if (ShouldPushBookmarkBarForVerticalTabs()) {
     // Insets are already applied from LayoutBookmarkAndInfoBar().
@@ -250,14 +254,19 @@ void BraveBrowserViewLayout::UpdateContentsContainerInsets(
   // Control contents's margin with sidebar & vertical tab state.
   gfx::Insets contents_margins = GetContentsMargins();
 
+  // In rounded corners mode, we need to include a little margin so we have
+  // somewhere to draw the shadow.
+  int contents_margin_for_rounded_corners =
+      BraveBrowser::GetRoundedCornersWebViewMargin(browser_view_->browser());
+
   // Don't need contents container's left or right margin with vertical tab as
   // vertical tab itself has sufficient padding.
   if (tabs::utils::ShouldShowVerticalTabs(browser_view_->browser()) &&
       !IsFullscreenForBrowser()) {
     if (tabs::utils::IsVerticalTabOnRight(browser_view_->browser())) {
-      contents_margins.set_right(0);
+      contents_margins.set_right(contents_margin_for_rounded_corners);
     } else {
-      contents_margins.set_left(0);
+      contents_margins.set_left(contents_margin_for_rounded_corners);
     }
   }
 
@@ -282,9 +291,9 @@ void BraveBrowserViewLayout::UpdateContentsContainerInsets(
   // If sidebar is shown in left-side, contents container doens't need its
   // left margin.
   if (sidebar_container_->sidebar_on_left()) {
-    contents_margins.set_left(0);
+    contents_margins.set_left(contents_margin_for_rounded_corners);
   } else {
-    contents_margins.set_right(0);
+    contents_margins.set_right(contents_margin_for_rounded_corners);
   }
   contents_container_bounds.Inset(contents_margins);
 }
diff --git a/browser/ui/views/frame/brave_contents_view_util.cc b/browser/ui/views/frame/brave_contents_view_util.cc
index f552fd8e1e84..2095f458554e 100644
--- a/browser/ui/views/frame/brave_contents_view_util.cc
+++ b/browser/ui/views/frame/brave_contents_view_util.cc
@@ -12,10 +12,9 @@ namespace {
 
 constexpr ViewShadow::ShadowParameters kShadow{
     .offset_x = 0,
-    .offset_y = 1,
-    .blur_radius = 4,
-    .shadow_color = SkColorSetA(SK_ColorBLACK, 0.07 * 255)};
-
+    .offset_y = 0,
+    .blur_radius = BraveContentsViewUtil::kMarginThickness,
+    .shadow_color = SkColorSetA(SK_ColorBLACK, 0.1 * 255)};
 }  // namespace
 
 std::unique_ptr<ViewShadow> BraveContentsViewUtil::CreateShadow(
diff --git a/browser/ui/views/frame/vertical_tab_strip_region_view.cc b/browser/ui/views/frame/vertical_tab_strip_region_view.cc
index b46447d25cf4..b50cf599af03 100644
--- a/browser/ui/views/frame/vertical_tab_strip_region_view.cc
+++ b/browser/ui/views/frame/vertical_tab_strip_region_view.cc
@@ -32,6 +32,7 @@
 #include "chrome/browser/ui/tabs/tab_style.h"
 #include "chrome/browser/ui/views/chrome_layout_provider.h"
 #include "chrome/browser/ui/views/frame/browser_non_client_frame_view.h"
+#include "chrome/browser/ui/views/frame/browser_view.h"
 #include "chrome/browser/ui/views/tabs/tab_strip_scroll_container.h"
 #include "chrome/browser/ui/views/toolbar/toolbar_button.h"
 #include "chrome/browser/ui/views/toolbar/toolbar_ink_drop_util.h"
@@ -1213,10 +1214,11 @@ void VerticalTabStripRegionView::UpdateBorder() {
            state_ == State::kFloating;
   };
 
+  int inset = 1 - BraveBrowser::GetRoundedCornersWebViewMargin(browser_);
   gfx::Insets border_insets =
       (!vertical_tab_on_right_.GetPrefName().empty() && *vertical_tab_on_right_)
-          ? gfx::Insets::TLBR(0, 1, 0, 0)
-          : gfx::Insets::TLBR(0, 0, 0, 1);
+          ? gfx::Insets::TLBR(0, inset, 0, 0)
+          : gfx::Insets::TLBR(0, 0, 0, inset);
 
   if (show_visible_border()) {
     SetBorder(views::CreateSolidSidedBorder(
diff --git a/browser/ui/views/side_panel/brave_side_panel.cc b/browser/ui/views/side_panel/brave_side_panel.cc
index 0e5db9541f01..4d321ed7f947 100644
--- a/browser/ui/views/side_panel/brave_side_panel.cc
+++ b/browser/ui/views/side_panel/brave_side_panel.cc
@@ -72,9 +72,16 @@ bool BraveSidePanel::IsRightAligned() {
 void BraveSidePanel::UpdateBorder() {
   if (BraveBrowser::ShouldUseBraveWebViewRoundedCorners(
           browser_view_->browser())) {
+    // In rounded corners mode we need to add the margin to the web contents
+    // container instead of the sidebar, so we have somewhere to render the
+    // shadow.
+    int content_margin =
+        -BraveBrowser::GetRoundedCornersWebViewMargin(browser_view_->browser());
     // Use a negative top border to hide the separator inserted by the upstream
     // side panel implementation.
-    SetBorder(views::CreateEmptyBorder(gfx::Insets::TLBR(-1, 0, 0, 0)));
+    SetBorder(views::CreateEmptyBorder(
+        gfx::Insets::TLBR(-1, IsRightAligned() ? content_margin : 0, 0,
+                          IsRightAligned() ? 0 : content_margin)));
     return;
   }
 

From 6c2a1104d48d678e1af4ef8ebc2bfe428256be73 Mon Sep 17 00:00:00 2001
From: Jay Harris <jay.harris@outlook.co.nz>
Date: Tue, 1 Oct 2024 13:40:19 +1300
Subject: [PATCH 2/9] [Sidebar]: Fix margins

---
 .../frame/vertical_tab_strip_region_view.cc   | 31 +++++++++++++------
 .../frame/vertical_tab_strip_region_view.h    |  3 +-
 .../ui/views/sidebar/sidebar_control_view.cc  | 22 ++++++++-----
 .../ui/views/sidebar/sidebar_control_view.h   |  2 ++
 4 files changed, 40 insertions(+), 18 deletions(-)

diff --git a/browser/ui/views/frame/vertical_tab_strip_region_view.cc b/browser/ui/views/frame/vertical_tab_strip_region_view.cc
index b50cf599af03..b82c8aef521f 100644
--- a/browser/ui/views/frame/vertical_tab_strip_region_view.cc
+++ b/browser/ui/views/frame/vertical_tab_strip_region_view.cc
@@ -11,6 +11,7 @@
 #include <utility>
 #include <vector>
 
+#include "base/functional/bind.h"
 #include "brave/app/vector_icons/vector_icons.h"
 #include "brave/browser/ui/brave_browser.h"
 #include "brave/browser/ui/color/brave_color_id.h"
@@ -32,7 +33,6 @@
 #include "chrome/browser/ui/tabs/tab_style.h"
 #include "chrome/browser/ui/views/chrome_layout_provider.h"
 #include "chrome/browser/ui/views/frame/browser_non_client_frame_view.h"
-#include "chrome/browser/ui/views/frame/browser_view.h"
 #include "chrome/browser/ui/views/tabs/tab_strip_scroll_container.h"
 #include "chrome/browser/ui/views/toolbar/toolbar_button.h"
 #include "chrome/browser/ui/views/toolbar/toolbar_ink_drop_util.h"
@@ -668,9 +668,13 @@ VerticalTabStripRegionView::VerticalTabStripRegionView(
 
   vertical_tab_on_right_.Init(
       brave_tabs::kVerticalTabsOnRight, browser()->profile()->GetPrefs(),
-      base::BindRepeating(
-          &VerticalTabStripRegionView::OnVerticalTabPositionChanged,
-          base::Unretained(this)));
+      base::BindRepeating(&VerticalTabStripRegionView::OnBrowserPanelsMoved,
+                          base::Unretained(this)));
+
+  sidebar_side_.Init(
+      prefs::kSidePanelHorizontalAlignment, prefs,
+      base::BindRepeating(&VerticalTabStripRegionView::OnBrowserPanelsMoved,
+                          base::Unretained(this)));
 
   widget_observation_.Observe(browser_view->GetWidget());
 
@@ -946,7 +950,7 @@ void VerticalTabStripRegionView::OnShowVerticalTabsPrefChanged() {
   UpdateBorder();
 }
 
-void VerticalTabStripRegionView::OnVerticalTabPositionChanged() {
+void VerticalTabStripRegionView::OnBrowserPanelsMoved() {
   UpdateBorder();
   PreferredSizeChanged();
 }
@@ -1214,11 +1218,18 @@ void VerticalTabStripRegionView::UpdateBorder() {
            state_ == State::kFloating;
   };
 
-  int inset = 1 - BraveBrowser::GetRoundedCornersWebViewMargin(browser_);
-  gfx::Insets border_insets =
-      (!vertical_tab_on_right_.GetPrefName().empty() && *vertical_tab_on_right_)
-          ? gfx::Insets::TLBR(0, inset, 0, 0)
-          : gfx::Insets::TLBR(0, 0, 0, inset);
+  // If the sidebar is on the same side as the vertical tab strip, we shouldn't
+  // take away the margin on the vertical tabs, because the sidebar will be
+  // between it and the web_contents.
+  bool is_on_right =
+      !vertical_tab_on_right_.GetPrefName().empty() && *vertical_tab_on_right_;
+  bool sidebar_on_same_side = sidebar_side_.GetValue() == is_on_right;
+  int inset =
+      1 - (sidebar_on_same_side
+               ? 0
+               : BraveBrowser::GetRoundedCornersWebViewMargin(browser_));
+  gfx::Insets border_insets = (is_on_right) ? gfx::Insets::TLBR(0, inset, 0, 0)
+                                            : gfx::Insets::TLBR(0, 0, 0, inset);
 
   if (show_visible_border()) {
     SetBorder(views::CreateSolidSidedBorder(
diff --git a/browser/ui/views/frame/vertical_tab_strip_region_view.h b/browser/ui/views/frame/vertical_tab_strip_region_view.h
index f978512297f6..9b556700a01f 100644
--- a/browser/ui/views/frame/vertical_tab_strip_region_view.h
+++ b/browser/ui/views/frame/vertical_tab_strip_region_view.h
@@ -144,7 +144,7 @@ class VerticalTabStripRegionView : public views::View,
   void UpdateStateAfterDragAndDropFinished(State original_state);
 
   void OnShowVerticalTabsPrefChanged();
-  void OnVerticalTabPositionChanged();
+  void OnBrowserPanelsMoved();
 
   void UpdateLayout(bool in_destruction = false);
 
@@ -202,6 +202,7 @@ class VerticalTabStripRegionView : public views::View,
   BooleanPrefMember collapsed_pref_;
   BooleanPrefMember expanded_state_per_window_pref_;
   BooleanPrefMember floating_mode_pref_;
+  BooleanPrefMember sidebar_side_;
 
   IntegerPrefMember expanded_width_pref_;
   int expanded_width_ = 220;
diff --git a/browser/ui/views/sidebar/sidebar_control_view.cc b/browser/ui/views/sidebar/sidebar_control_view.cc
index 4157e4bb8726..014885452082 100644
--- a/browser/ui/views/sidebar/sidebar_control_view.cc
+++ b/browser/ui/views/sidebar/sidebar_control_view.cc
@@ -86,13 +86,14 @@ void SidebarControlView::UpdateBackgroundAndBorder() {
   if (const ui::ColorProvider* color_provider = GetColorProvider()) {
     SetBackground(
         views::CreateSolidBackground(color_provider->GetColor(kColorToolbar)));
-    if (!BraveBrowser::ShouldUseBraveWebViewRoundedCorners(browser_)) {
-      constexpr int kBorderThickness = 1;
-      SetBorder(views::CreateSolidSidedBorder(
-          gfx::Insets::TLBR(0, sidebar_on_left_ ? 0 : kBorderThickness, 0,
-                            sidebar_on_left_ ? kBorderThickness : 0),
-          color_provider->GetColor(kColorToolbarContentAreaSeparator)));
-    }
+    bool open =
+        browser_->sidebar_controller()->model()->active_index().has_value();
+    int border_thickness =
+        1 - (open ? 0 : BraveBrowser::GetRoundedCornersWebViewMargin(browser_));
+    SetBorder(views::CreateSolidSidedBorder(
+        gfx::Insets::TLBR(0, sidebar_on_left_ ? 0 : border_thickness, 0,
+                          sidebar_on_left_ ? border_thickness : 0),
+        color_provider->GetColor(kColorToolbarContentAreaSeparator)));
   }
 }
 
@@ -168,6 +169,13 @@ void SidebarControlView::OnItemRemoved(size_t index) {
   UpdateItemAddButtonState();
 }
 
+void SidebarControlView::OnActiveIndexChanged(std::optional<size_t> old_index,
+                                              std::optional<size_t> new_index) {
+  if (old_index.has_value() != new_index.has_value()) {
+    UpdateBackgroundAndBorder();
+  }
+}
+
 void SidebarControlView::AddChildViews() {
   sidebar_items_view_ =
       AddChildView(std::make_unique<SidebarItemsScrollView>(browser_));
diff --git a/browser/ui/views/sidebar/sidebar_control_view.h b/browser/ui/views/sidebar/sidebar_control_view.h
index 2658ac3450ed..8d34d5ea7cc6 100644
--- a/browser/ui/views/sidebar/sidebar_control_view.h
+++ b/browser/ui/views/sidebar/sidebar_control_view.h
@@ -69,6 +69,8 @@ class SidebarControlView : public views::View,
                    size_t index,
                    bool user_gesture) override;
   void OnItemRemoved(size_t index) override;
+  void OnActiveIndexChanged(std::optional<size_t> old_index,
+                            std::optional<size_t> new_index) override;
 
   void Update();
 

From fb8b254c10a0c5fb352e38775b242037e395161e Mon Sep 17 00:00:00 2001
From: Jay Harris <jay.harris@outlook.co.nz>
Date: Thu, 3 Oct 2024 10:52:42 +1300
Subject: [PATCH 3/9] Refactoring to set the border on the panel instead

---
 .../views/frame/brave_browser_view_layout.cc   |  8 +++++++-
 .../ui/views/frame/brave_contents_view_util.cc |  2 +-
 .../ui/views/side_panel/brave_side_panel.cc    | 10 +++++-----
 .../ui/views/sidebar/sidebar_control_view.cc   | 18 +++++-------------
 .../ui/views/sidebar/sidebar_control_view.h    |  2 --
 5 files changed, 18 insertions(+), 22 deletions(-)

diff --git a/browser/ui/views/frame/brave_browser_view_layout.cc b/browser/ui/views/frame/brave_browser_view_layout.cc
index 2af91c9c9bee..dd5f88a2d37e 100644
--- a/browser/ui/views/frame/brave_browser_view_layout.cc
+++ b/browser/ui/views/frame/brave_browser_view_layout.cc
@@ -231,7 +231,13 @@ void BraveBrowserViewLayout::LayoutSideBar(gfx::Rect& contents_bounds) {
   // Side panel doesn't need margin as sidebar UI and contents container
   // will have margins if needed.
   gfx::Insets panel_margins = GetContentsMargins();
-  panel_margins.set_left_right(0, 0);
+
+  // We need somewhere to draw the panel shadow in rounded mode, so don't clear
+  // the margins.
+  if (!BraveBrowser::ShouldUseBraveWebViewRoundedCorners(
+          browser_view_->browser())) {
+    panel_margins.set_left_right(0, 0);
+  }
   sidebar_container_->side_panel()->SetProperty(views::kMarginsKey,
                                                 panel_margins);
 
diff --git a/browser/ui/views/frame/brave_contents_view_util.cc b/browser/ui/views/frame/brave_contents_view_util.cc
index 2095f458554e..d062167989ff 100644
--- a/browser/ui/views/frame/brave_contents_view_util.cc
+++ b/browser/ui/views/frame/brave_contents_view_util.cc
@@ -14,7 +14,7 @@ constexpr ViewShadow::ShadowParameters kShadow{
     .offset_x = 0,
     .offset_y = 0,
     .blur_radius = BraveContentsViewUtil::kMarginThickness,
-    .shadow_color = SkColorSetA(SK_ColorBLACK, 0.1 * 255)};
+    .shadow_color = SkColorSetA(SK_ColorBLACK, 0.8 * 255)};
 }  // namespace
 
 std::unique_ptr<ViewShadow> BraveContentsViewUtil::CreateShadow(
diff --git a/browser/ui/views/side_panel/brave_side_panel.cc b/browser/ui/views/side_panel/brave_side_panel.cc
index 4d321ed7f947..1754d9d84160 100644
--- a/browser/ui/views/side_panel/brave_side_panel.cc
+++ b/browser/ui/views/side_panel/brave_side_panel.cc
@@ -24,8 +24,10 @@
 #include "chrome/browser/ui/views/side_panel/side_panel_util.h"
 #include "ui/base/metadata/metadata_impl_macros.h"
 #include "ui/color/color_provider.h"
+#include "ui/gfx/geometry/insets.h"
 #include "ui/views/background.h"
 #include "ui/views/border.h"
+#include "ui/views/view_class_properties.h"
 
 BraveSidePanel::BraveSidePanel(BrowserView* browser_view,
                                HorizontalAlignment horizontal_alignment)
@@ -75,13 +77,11 @@ void BraveSidePanel::UpdateBorder() {
     // In rounded corners mode we need to add the margin to the web contents
     // container instead of the sidebar, so we have somewhere to render the
     // shadow.
-    int content_margin =
-        -BraveBrowser::GetRoundedCornersWebViewMargin(browser_view_->browser());
+    // int content_margin =
+    //     -BraveBrowser::GetRoundedCornersWebViewMargin(browser_view_->browser());
     // Use a negative top border to hide the separator inserted by the upstream
     // side panel implementation.
-    SetBorder(views::CreateEmptyBorder(
-        gfx::Insets::TLBR(-1, IsRightAligned() ? content_margin : 0, 0,
-                          IsRightAligned() ? 0 : content_margin)));
+    SetBorder(views::NullBorder());
     return;
   }
 
diff --git a/browser/ui/views/sidebar/sidebar_control_view.cc b/browser/ui/views/sidebar/sidebar_control_view.cc
index 014885452082..c37459cfd19d 100644
--- a/browser/ui/views/sidebar/sidebar_control_view.cc
+++ b/browser/ui/views/sidebar/sidebar_control_view.cc
@@ -19,8 +19,10 @@
 #include "brave/grit/brave_generated_resources.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/browser_command_controller.h"
+#include "chrome/browser/ui/browser_window/public/browser_window_features.h"
 #include "chrome/browser/ui/color/chrome_color_id.h"
 #include "chrome/browser/ui/singleton_tabs.h"
+#include "chrome/browser/ui/views/side_panel/side_panel_ui.h"
 #include "chrome/common/pref_names.h"
 #include "components/prefs/pref_service.h"
 #include "ui/base/l10n/l10n_util.h"
@@ -86,14 +88,11 @@ void SidebarControlView::UpdateBackgroundAndBorder() {
   if (const ui::ColorProvider* color_provider = GetColorProvider()) {
     SetBackground(
         views::CreateSolidBackground(color_provider->GetColor(kColorToolbar)));
-    bool open =
-        browser_->sidebar_controller()->model()->active_index().has_value();
     int border_thickness =
-        1 - (open ? 0 : BraveBrowser::GetRoundedCornersWebViewMargin(browser_));
-    SetBorder(views::CreateSolidSidedBorder(
+        1 - BraveBrowser::GetRoundedCornersWebViewMargin(browser_);
+    SetBorder(views::CreateEmptyBorder(
         gfx::Insets::TLBR(0, sidebar_on_left_ ? 0 : border_thickness, 0,
-                          sidebar_on_left_ ? border_thickness : 0),
-        color_provider->GetColor(kColorToolbarContentAreaSeparator)));
+                          sidebar_on_left_ ? border_thickness : 0)));
   }
 }
 
@@ -169,13 +168,6 @@ void SidebarControlView::OnItemRemoved(size_t index) {
   UpdateItemAddButtonState();
 }
 
-void SidebarControlView::OnActiveIndexChanged(std::optional<size_t> old_index,
-                                              std::optional<size_t> new_index) {
-  if (old_index.has_value() != new_index.has_value()) {
-    UpdateBackgroundAndBorder();
-  }
-}
-
 void SidebarControlView::AddChildViews() {
   sidebar_items_view_ =
       AddChildView(std::make_unique<SidebarItemsScrollView>(browser_));
diff --git a/browser/ui/views/sidebar/sidebar_control_view.h b/browser/ui/views/sidebar/sidebar_control_view.h
index 8d34d5ea7cc6..2658ac3450ed 100644
--- a/browser/ui/views/sidebar/sidebar_control_view.h
+++ b/browser/ui/views/sidebar/sidebar_control_view.h
@@ -69,8 +69,6 @@ class SidebarControlView : public views::View,
                    size_t index,
                    bool user_gesture) override;
   void OnItemRemoved(size_t index) override;
-  void OnActiveIndexChanged(std::optional<size_t> old_index,
-                            std::optional<size_t> new_index) override;
 
   void Update();
 

From e52e86fe0d48d1b2df4e693681eb0032031eae84 Mon Sep 17 00:00:00 2001
From: Jay Harris <jay.harris@outlook.co.nz>
Date: Thu, 3 Oct 2024 11:24:36 +1300
Subject: [PATCH 4/9] Begin fixing panels

---
 browser/ui/views/side_panel/brave_side_panel.cc           | 7 -------
 browser/ui/views/side_panel/brave_side_panel_view_base.cc | 6 ++++--
 2 files changed, 4 insertions(+), 9 deletions(-)

diff --git a/browser/ui/views/side_panel/brave_side_panel.cc b/browser/ui/views/side_panel/brave_side_panel.cc
index 1754d9d84160..ac0c79da87dd 100644
--- a/browser/ui/views/side_panel/brave_side_panel.cc
+++ b/browser/ui/views/side_panel/brave_side_panel.cc
@@ -74,13 +74,6 @@ bool BraveSidePanel::IsRightAligned() {
 void BraveSidePanel::UpdateBorder() {
   if (BraveBrowser::ShouldUseBraveWebViewRoundedCorners(
           browser_view_->browser())) {
-    // In rounded corners mode we need to add the margin to the web contents
-    // container instead of the sidebar, so we have somewhere to render the
-    // shadow.
-    // int content_margin =
-    //     -BraveBrowser::GetRoundedCornersWebViewMargin(browser_view_->browser());
-    // Use a negative top border to hide the separator inserted by the upstream
-    // side panel implementation.
     SetBorder(views::NullBorder());
     return;
   }
diff --git a/browser/ui/views/side_panel/brave_side_panel_view_base.cc b/browser/ui/views/side_panel/brave_side_panel_view_base.cc
index d82938b5baec..6d30427acddc 100644
--- a/browser/ui/views/side_panel/brave_side_panel_view_base.cc
+++ b/browser/ui/views/side_panel/brave_side_panel_view_base.cc
@@ -6,6 +6,7 @@
 #include "brave/browser/ui/views/side_panel/brave_side_panel_view_base.h"
 
 #include "brave/browser/ui/color/brave_color_id.h"
+#include "brave/browser/ui/views/frame/brave_contents_view_util.h"
 #include "chrome/browser/ui/views/side_panel/side_panel_content_proxy.h"
 #include "chrome/browser/ui/views/side_panel/side_panel_util.h"
 #include "ui/base/metadata/metadata_impl_macros.h"
@@ -23,8 +24,9 @@ BraveSidePanelViewBase::BraveSidePanelViewBase() {
   // NOTE: If we use our own reading list page and it has loading spinner, maybe
   // we can set `true` here.
   SidePanelUtil::GetSidePanelContentProxy(this)->SetAvailable(false);
-  SetBackground(
-      views::CreateThemedSolidBackground(kColorSidebarPanelHeaderBackground));
+  SetBackground(views::CreateRoundedRectBackground(
+      kColorSidebarPanelHeaderBackground,
+      BraveContentsViewUtil::kMarginThickness));
 }
 
 BraveSidePanelViewBase::~BraveSidePanelViewBase() = default;

From 87d5579e99458b8607a5dc29eaf9ff695b10b02b Mon Sep 17 00:00:00 2001
From: Jay Harris <jay.harris@outlook.co.nz>
Date: Thu, 3 Oct 2024 13:40:30 +1300
Subject: [PATCH 5/9] Add radius to all corners

---
 .../views/frame/brave_browser_view_layout.cc  | 22 ++++++++++++-------
 .../views/frame/brave_contents_view_util.cc   |  2 +-
 .../side_panel/brave_side_panel_view_base.cc  |  6 ++---
 .../side_panel/side_panel_web_ui_view.cc      | 11 ++++------
 4 files changed, 21 insertions(+), 20 deletions(-)

diff --git a/browser/ui/views/frame/brave_browser_view_layout.cc b/browser/ui/views/frame/brave_browser_view_layout.cc
index dd5f88a2d37e..5af08357d5c0 100644
--- a/browser/ui/views/frame/brave_browser_view_layout.cc
+++ b/browser/ui/views/frame/brave_browser_view_layout.cc
@@ -208,8 +208,8 @@ void BraveBrowserViewLayout::LayoutSideBar(gfx::Rect& contents_bounds) {
 #endif
 
   gfx::Rect separator_bounds;
-
-  if (sidebar_container_->sidebar_on_left()) {
+  const bool on_left = sidebar_container_->sidebar_on_left();
+  if (on_left) {
     contents_bounds.set_x(contents_bounds.x() + sidebar_bounds.width());
 
     // When vertical tabs and the sidebar are adjacent, add a separator between
@@ -228,14 +228,20 @@ void BraveBrowserViewLayout::LayoutSideBar(gfx::Rect& contents_bounds) {
     sidebar_bounds.set_x(contents_bounds.right());
   }
 
-  // Side panel doesn't need margin as sidebar UI and contents container
-  // will have margins if needed.
   gfx::Insets panel_margins = GetContentsMargins();
-
-  // We need somewhere to draw the panel shadow in rounded mode, so don't clear
-  // the margins.
-  if (!BraveBrowser::ShouldUseBraveWebViewRoundedCorners(
+  if (BraveBrowser::ShouldUseBraveWebViewRoundedCorners(
           browser_view_->browser())) {
+    // In rounded mode, there is already a gap between the sidebar and the main
+    // contents view, so we only remove from the margin from that side (we need
+    // to keep it between the sidebar controls and the sidebar content).
+    if (on_left) {
+      panel_margins.set_right(0);
+    } else {
+      panel_margins.set_left(0);
+    }
+  } else {
+    // Side panel doesn't need margin as sidebar UI and contents container
+    // will have margins if needed.
     panel_margins.set_left_right(0, 0);
   }
   sidebar_container_->side_panel()->SetProperty(views::kMarginsKey,
diff --git a/browser/ui/views/frame/brave_contents_view_util.cc b/browser/ui/views/frame/brave_contents_view_util.cc
index d062167989ff..2095f458554e 100644
--- a/browser/ui/views/frame/brave_contents_view_util.cc
+++ b/browser/ui/views/frame/brave_contents_view_util.cc
@@ -14,7 +14,7 @@ constexpr ViewShadow::ShadowParameters kShadow{
     .offset_x = 0,
     .offset_y = 0,
     .blur_radius = BraveContentsViewUtil::kMarginThickness,
-    .shadow_color = SkColorSetA(SK_ColorBLACK, 0.8 * 255)};
+    .shadow_color = SkColorSetA(SK_ColorBLACK, 0.1 * 255)};
 }  // namespace
 
 std::unique_ptr<ViewShadow> BraveContentsViewUtil::CreateShadow(
diff --git a/browser/ui/views/side_panel/brave_side_panel_view_base.cc b/browser/ui/views/side_panel/brave_side_panel_view_base.cc
index 6d30427acddc..d82938b5baec 100644
--- a/browser/ui/views/side_panel/brave_side_panel_view_base.cc
+++ b/browser/ui/views/side_panel/brave_side_panel_view_base.cc
@@ -6,7 +6,6 @@
 #include "brave/browser/ui/views/side_panel/brave_side_panel_view_base.h"
 
 #include "brave/browser/ui/color/brave_color_id.h"
-#include "brave/browser/ui/views/frame/brave_contents_view_util.h"
 #include "chrome/browser/ui/views/side_panel/side_panel_content_proxy.h"
 #include "chrome/browser/ui/views/side_panel/side_panel_util.h"
 #include "ui/base/metadata/metadata_impl_macros.h"
@@ -24,9 +23,8 @@ BraveSidePanelViewBase::BraveSidePanelViewBase() {
   // NOTE: If we use our own reading list page and it has loading spinner, maybe
   // we can set `true` here.
   SidePanelUtil::GetSidePanelContentProxy(this)->SetAvailable(false);
-  SetBackground(views::CreateRoundedRectBackground(
-      kColorSidebarPanelHeaderBackground,
-      BraveContentsViewUtil::kMarginThickness));
+  SetBackground(
+      views::CreateThemedSolidBackground(kColorSidebarPanelHeaderBackground));
 }
 
 BraveSidePanelViewBase::~BraveSidePanelViewBase() = default;
diff --git a/chromium_src/chrome/browser/ui/views/side_panel/side_panel_web_ui_view.cc b/chromium_src/chrome/browser/ui/views/side_panel/side_panel_web_ui_view.cc
index e83e9f1a6b9d..42a9e8a7bcae 100644
--- a/chromium_src/chrome/browser/ui/views/side_panel/side_panel_web_ui_view.cc
+++ b/chromium_src/chrome/browser/ui/views/side_panel/side_panel_web_ui_view.cc
@@ -3,17 +3,14 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
  * You can obtain one at https://mozilla.org/MPL/2.0/. */
 
+#include "src/chrome/browser/ui/views/side_panel/side_panel_web_ui_view.cc"
+
 #include "brave/browser/brave_browser_features.h"
 #include "brave/browser/ui/views/frame/brave_contents_view_util.h"
 
-#include "src/chrome/browser/ui/views/side_panel/side_panel_web_ui_view.cc"
-
 void SidePanelWebUIView::AddedToWidget() {
   if (base::FeatureList::IsEnabled(features::kBraveWebViewRoundedCorners)) {
-    // Side panel WebUI views are positioned at the bottom of the side panel. In
-    // order to maintain rounded corners around the side panel, give the web
-    // contents native view rounded corners on the bottom.
-    constexpr auto radius = BraveContentsViewUtil::kBorderRadius;
-    holder()->SetCornerRadii(gfx::RoundedCornersF(0, 0, radius, radius));
+    constexpr auto kRadius = BraveContentsViewUtil::kBorderRadius;
+    holder()->SetCornerRadii(gfx::RoundedCornersF(kRadius));
   }
 }

From 6520b1204b807d813fa8a3fd6e0bc212fd1eb007 Mon Sep 17 00:00:00 2001
From: Jay Harris <jay.harris@outlook.co.nz>
Date: Thu, 3 Oct 2024 14:59:24 +1300
Subject: [PATCH 6/9] Cleanup for PR

---
 browser/ui/brave_browser.cc                              | 7 -------
 browser/ui/brave_browser.h                               | 1 -
 browser/ui/views/frame/brave_browser_view_layout.cc      | 3 ++-
 browser/ui/views/frame/brave_contents_view_util.cc       | 8 ++++++++
 browser/ui/views/frame/brave_contents_view_util.h        | 6 ++++++
 browser/ui/views/frame/vertical_tab_strip_region_view.cc | 8 +++++---
 browser/ui/views/side_panel/brave_side_panel.cc          | 6 +++---
 browser/ui/views/sidebar/sidebar_container_view.cc       | 5 ++++-
 browser/ui/views/sidebar/sidebar_control_view.cc         | 3 ++-
 9 files changed, 30 insertions(+), 17 deletions(-)

diff --git a/browser/ui/brave_browser.cc b/browser/ui/brave_browser.cc
index a3dbdfd94aa0..350f9f2cef03 100644
--- a/browser/ui/brave_browser.cc
+++ b/browser/ui/brave_browser.cc
@@ -18,7 +18,6 @@
 #include "brave/browser/ui/brave_file_select_utils.h"
 #include "brave/browser/ui/tabs/brave_tab_prefs.h"
 #include "brave/browser/ui/tabs/features.h"
-#include "brave/browser/ui/views/frame/brave_contents_view_util.h"
 #include "brave/components/constants/pref_names.h"
 #include "chrome/browser/lifetime/browser_close_manager.h"
 #include "chrome/browser/profiles/profile.h"
@@ -58,12 +57,6 @@ bool BraveBrowser::ShouldUseBraveWebViewRoundedCorners(Browser* browser) {
          browser->is_type_normal();
 }
 
-int BraveBrowser::GetRoundedCornersWebViewMargin(Browser* browser) {
-  return ShouldUseBraveWebViewRoundedCorners(browser)
-             ? BraveContentsViewUtil::kMarginThickness
-             : 0;
-}
-
 BraveBrowser::BraveBrowser(const CreateParams& params) : Browser(params) {
 #if defined(TOOLKIT_VIEWS)
   if (!sidebar::CanUseSidebar(this)) {
diff --git a/browser/ui/brave_browser.h b/browser/ui/brave_browser.h
index 15b70fe01ce2..f4e02d2b1e3d 100644
--- a/browser/ui/brave_browser.h
+++ b/browser/ui/brave_browser.h
@@ -32,7 +32,6 @@ class BraveBrowser : public Browser {
   BraveBrowser& operator=(const BraveBrowser&) = delete;
 
   static bool ShouldUseBraveWebViewRoundedCorners(Browser* browser);
-  static int GetRoundedCornersWebViewMargin(Browser* browser);
 
   // Browser overrides:
   void ScheduleUIUpdate(content::WebContents* source,
diff --git a/browser/ui/views/frame/brave_browser_view_layout.cc b/browser/ui/views/frame/brave_browser_view_layout.cc
index 5af08357d5c0..b84cf4b1ca0b 100644
--- a/browser/ui/views/frame/brave_browser_view_layout.cc
+++ b/browser/ui/views/frame/brave_browser_view_layout.cc
@@ -269,7 +269,8 @@ void BraveBrowserViewLayout::UpdateContentsContainerInsets(
   // In rounded corners mode, we need to include a little margin so we have
   // somewhere to draw the shadow.
   int contents_margin_for_rounded_corners =
-      BraveBrowser::GetRoundedCornersWebViewMargin(browser_view_->browser());
+      BraveContentsViewUtil::GetRoundedCornersWebViewMargin(
+          browser_view_->browser());
 
   // Don't need contents container's left or right margin with vertical tab as
   // vertical tab itself has sufficient padding.
diff --git a/browser/ui/views/frame/brave_contents_view_util.cc b/browser/ui/views/frame/brave_contents_view_util.cc
index 2095f458554e..35140dc3cc98 100644
--- a/browser/ui/views/frame/brave_contents_view_util.cc
+++ b/browser/ui/views/frame/brave_contents_view_util.cc
@@ -5,6 +5,8 @@
 
 #include "brave/browser/ui/views/frame/brave_contents_view_util.h"
 
+#include "brave/browser/ui/brave_browser.h"
+#include "chrome/browser/ui/browser.h"
 #include "ui/compositor/layer.h"
 #include "ui/views/view.h"
 
@@ -25,3 +27,9 @@ std::unique_ptr<ViewShadow> BraveContentsViewUtil::CreateShadow(
   view->layer()->SetIsFastRoundedCorner(true);
   return shadow;
 }
+
+int BraveContentsViewUtil::GetRoundedCornersWebViewMargin(Browser* browser) {
+  return BraveBrowser::ShouldUseBraveWebViewRoundedCorners(browser)
+             ? BraveContentsViewUtil::kMarginThickness
+             : 0;
+}
diff --git a/browser/ui/views/frame/brave_contents_view_util.h b/browser/ui/views/frame/brave_contents_view_util.h
index 937f4d4fe819..42aaee9a282f 100644
--- a/browser/ui/views/frame/brave_contents_view_util.h
+++ b/browser/ui/views/frame/brave_contents_view_util.h
@@ -10,6 +10,8 @@
 
 #include "brave/browser/ui/views/view_shadow.h"
 
+class Browser;
+
 namespace views {
 class View;
 }
@@ -28,6 +30,10 @@ class BraveContentsViewUtil {
 
   // Creates a drop shadow for the specified content area view.
   static std::unique_ptr<ViewShadow> CreateShadow(views::View* view);
+
+  // If rounded corners are enabled, returns the additional margin required to
+  // get the shadow to display properly. Otherwise 0.
+  static int GetRoundedCornersWebViewMargin(Browser* browser);
 };
 
 #endif  // BRAVE_BROWSER_UI_VIEWS_FRAME_BRAVE_CONTENTS_VIEW_UTIL_H_
diff --git a/browser/ui/views/frame/vertical_tab_strip_region_view.cc b/browser/ui/views/frame/vertical_tab_strip_region_view.cc
index b82c8aef521f..8c348413de62 100644
--- a/browser/ui/views/frame/vertical_tab_strip_region_view.cc
+++ b/browser/ui/views/frame/vertical_tab_strip_region_view.cc
@@ -16,6 +16,7 @@
 #include "brave/browser/ui/brave_browser.h"
 #include "brave/browser/ui/color/brave_color_id.h"
 #include "brave/browser/ui/tabs/brave_tab_prefs.h"
+#include "brave/browser/ui/views/frame/brave_contents_view_util.h"
 #include "brave/browser/ui/views/tabs/brave_new_tab_button.h"
 #include "brave/browser/ui/views/tabs/brave_tab_search_button.h"
 #include "brave/browser/ui/views/tabs/brave_tab_strip_layout_helper.h"
@@ -1225,9 +1226,10 @@ void VerticalTabStripRegionView::UpdateBorder() {
       !vertical_tab_on_right_.GetPrefName().empty() && *vertical_tab_on_right_;
   bool sidebar_on_same_side = sidebar_side_.GetValue() == is_on_right;
   int inset =
-      1 - (sidebar_on_same_side
-               ? 0
-               : BraveBrowser::GetRoundedCornersWebViewMargin(browser_));
+      1 -
+      (sidebar_on_same_side
+           ? 0
+           : BraveContentsViewUtil::GetRoundedCornersWebViewMargin(browser_));
   gfx::Insets border_insets = (is_on_right) ? gfx::Insets::TLBR(0, inset, 0, 0)
                                             : gfx::Insets::TLBR(0, 0, 0, inset);
 
diff --git a/browser/ui/views/side_panel/brave_side_panel.cc b/browser/ui/views/side_panel/brave_side_panel.cc
index ac0c79da87dd..0e5db9541f01 100644
--- a/browser/ui/views/side_panel/brave_side_panel.cc
+++ b/browser/ui/views/side_panel/brave_side_panel.cc
@@ -24,10 +24,8 @@
 #include "chrome/browser/ui/views/side_panel/side_panel_util.h"
 #include "ui/base/metadata/metadata_impl_macros.h"
 #include "ui/color/color_provider.h"
-#include "ui/gfx/geometry/insets.h"
 #include "ui/views/background.h"
 #include "ui/views/border.h"
-#include "ui/views/view_class_properties.h"
 
 BraveSidePanel::BraveSidePanel(BrowserView* browser_view,
                                HorizontalAlignment horizontal_alignment)
@@ -74,7 +72,9 @@ bool BraveSidePanel::IsRightAligned() {
 void BraveSidePanel::UpdateBorder() {
   if (BraveBrowser::ShouldUseBraveWebViewRoundedCorners(
           browser_view_->browser())) {
-    SetBorder(views::NullBorder());
+    // Use a negative top border to hide the separator inserted by the upstream
+    // side panel implementation.
+    SetBorder(views::CreateEmptyBorder(gfx::Insets::TLBR(-1, 0, 0, 0)));
     return;
   }
 
diff --git a/browser/ui/views/sidebar/sidebar_container_view.cc b/browser/ui/views/sidebar/sidebar_container_view.cc
index 47e050963485..bed8a752f1a8 100644
--- a/browser/ui/views/sidebar/sidebar_container_view.cc
+++ b/browser/ui/views/sidebar/sidebar_container_view.cc
@@ -528,7 +528,10 @@ void SidebarContainerView::ShowSidebar(bool show_side_panel) {
 
   // Calculate the start & end width for animation. Both are used when
   // calculating preferred width during the show animation.
-  animation_start_width_ = width();
+  // Note: as margins of |side_panel_| are part of |width()| we need to remove
+  // them when calculating the ideal start width of the contents.
+  animation_start_width_ =
+      width() - side_panel_->GetProperty(views::kMarginsKey)->width();
   animation_end_width_ = sidebar_control_view_->GetPreferredSize().width();
   if (show_side_panel) {
     animation_end_width_ += side_panel_->GetPreferredSize().width();
diff --git a/browser/ui/views/sidebar/sidebar_control_view.cc b/browser/ui/views/sidebar/sidebar_control_view.cc
index c37459cfd19d..17247b198c35 100644
--- a/browser/ui/views/sidebar/sidebar_control_view.cc
+++ b/browser/ui/views/sidebar/sidebar_control_view.cc
@@ -11,6 +11,7 @@
 #include "brave/browser/ui/sidebar/sidebar_controller.h"
 #include "brave/browser/ui/sidebar/sidebar_service_factory.h"
 #include "brave/browser/ui/sidebar/sidebar_utils.h"
+#include "brave/browser/ui/views/frame/brave_contents_view_util.h"
 #include "brave/browser/ui/views/sidebar/sidebar_item_add_button.h"
 #include "brave/browser/ui/views/sidebar/sidebar_items_scroll_view.h"
 #include "brave/components/l10n/common/localization_util.h"
@@ -89,7 +90,7 @@ void SidebarControlView::UpdateBackgroundAndBorder() {
     SetBackground(
         views::CreateSolidBackground(color_provider->GetColor(kColorToolbar)));
     int border_thickness =
-        1 - BraveBrowser::GetRoundedCornersWebViewMargin(browser_);
+        1 - BraveContentsViewUtil::GetRoundedCornersWebViewMargin(browser_);
     SetBorder(views::CreateEmptyBorder(
         gfx::Insets::TLBR(0, sidebar_on_left_ ? 0 : border_thickness, 0,
                           sidebar_on_left_ ? border_thickness : 0)));

From 57c10686bf66a6f9b8938e5f41c4f790025d7eac Mon Sep 17 00:00:00 2001
From: Jay Harris <jay.harris@outlook.co.nz>
Date: Thu, 3 Oct 2024 15:38:12 +1300
Subject: [PATCH 7/9] Fix DCHECK

---
 browser/ui/views/frame/vertical_tab_strip_region_view.cc    | 6 ++++--
 .../browser/ui/views/side_panel/side_panel_web_ui_view.cc   | 4 ++--
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/browser/ui/views/frame/vertical_tab_strip_region_view.cc b/browser/ui/views/frame/vertical_tab_strip_region_view.cc
index 8c348413de62..afb1e2ec9fe1 100644
--- a/browser/ui/views/frame/vertical_tab_strip_region_view.cc
+++ b/browser/ui/views/frame/vertical_tab_strip_region_view.cc
@@ -1097,8 +1097,10 @@ void VerticalTabStripRegionView::OnBoundsChanged(
 #if DCHECK_IS_ON()
   if (auto width = GetContentsBounds().width();
       width && !IsBrowserFullscren()) {
-    CHECK_GE(width, tabs::kVerticalTabMinWidth +
-                        tabs::kMarginForVerticalTabContainers * 2);
+    CHECK_GE(
+        width,
+        tabs::kVerticalTabMinWidth + tabs::kMarginForVerticalTabContainers * 2 -
+            BraveContentsViewUtil::GetRoundedCornersWebViewMargin(browser_));
   }
 #endif
 }
diff --git a/chromium_src/chrome/browser/ui/views/side_panel/side_panel_web_ui_view.cc b/chromium_src/chrome/browser/ui/views/side_panel/side_panel_web_ui_view.cc
index 42a9e8a7bcae..cb35df44d575 100644
--- a/chromium_src/chrome/browser/ui/views/side_panel/side_panel_web_ui_view.cc
+++ b/chromium_src/chrome/browser/ui/views/side_panel/side_panel_web_ui_view.cc
@@ -3,11 +3,11 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
  * You can obtain one at https://mozilla.org/MPL/2.0/. */
 
-#include "src/chrome/browser/ui/views/side_panel/side_panel_web_ui_view.cc"
-
 #include "brave/browser/brave_browser_features.h"
 #include "brave/browser/ui/views/frame/brave_contents_view_util.h"
 
+#include "src/chrome/browser/ui/views/side_panel/side_panel_web_ui_view.cc"
+
 void SidePanelWebUIView::AddedToWidget() {
   if (base::FeatureList::IsEnabled(features::kBraveWebViewRoundedCorners)) {
     constexpr auto kRadius = BraveContentsViewUtil::kBorderRadius;

From f9a0f751e31d5e2c851b14f92ac43ff09d41dd4e Mon Sep 17 00:00:00 2001
From: Jay Harris <jay.harris@outlook.co.nz>
Date: Fri, 4 Oct 2024 13:51:48 +1300
Subject: [PATCH 8/9] Fix flickering

---
 browser/ui/views/sidebar/sidebar_container_view.cc | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/browser/ui/views/sidebar/sidebar_container_view.cc b/browser/ui/views/sidebar/sidebar_container_view.cc
index bed8a752f1a8..f690bf18e907 100644
--- a/browser/ui/views/sidebar/sidebar_container_view.cc
+++ b/browser/ui/views/sidebar/sidebar_container_view.cc
@@ -528,13 +528,14 @@ void SidebarContainerView::ShowSidebar(bool show_side_panel) {
 
   // Calculate the start & end width for animation. Both are used when
   // calculating preferred width during the show animation.
-  // Note: as margins of |side_panel_| are part of |width()| we need to remove
-  // them when calculating the ideal start width of the contents.
-  animation_start_width_ =
-      width() - side_panel_->GetProperty(views::kMarginsKey)->width();
+  animation_start_width_ = width();
   animation_end_width_ = sidebar_control_view_->GetPreferredSize().width();
   if (show_side_panel) {
-    animation_end_width_ += side_panel_->GetPreferredSize().width();
+    // Note: as margins of |side_panel_| are part of |width()| we need to add
+    // them when calculating the ideal width of the contents.
+    animation_end_width_ +=
+        side_panel_->GetPreferredSize().width() +
+        side_panel_->GetProperty(views::kMarginsKey)->width();
   }
 
   // Don't need event detect widget when sidebar gets visible.

From 651504a7ecc77c89de96034abe3e13e25283cfd7 Mon Sep 17 00:00:00 2001
From: Jay Harris <jay.harris@outlook.co.nz>
Date: Fri, 4 Oct 2024 14:03:01 +1300
Subject: [PATCH 9/9] Fix PrefMember crash

---
 browser/ui/views/frame/vertical_tab_strip_region_view.cc | 4 +++-
 browser/ui/views/frame/vertical_tab_strip_region_view.h  | 2 +-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/browser/ui/views/frame/vertical_tab_strip_region_view.cc b/browser/ui/views/frame/vertical_tab_strip_region_view.cc
index afb1e2ec9fe1..9f9838d79e1c 100644
--- a/browser/ui/views/frame/vertical_tab_strip_region_view.cc
+++ b/browser/ui/views/frame/vertical_tab_strip_region_view.cc
@@ -658,7 +658,6 @@ VerticalTabStripRegionView::VerticalTabStripRegionView(
       base::BindRepeating(
           &VerticalTabStripRegionView::OnFloatingModePrefChanged,
           base::Unretained(this)));
-  OnFloatingModePrefChanged();
 
 #if BUILDFLAG(IS_MAC)
   show_toolbar_on_fullscreen_pref_.Init(
@@ -686,6 +685,9 @@ VerticalTabStripRegionView::VerticalTabStripRegionView(
          BrowserList::GetInstance()->end())
       << "Browser shouldn't be added at this point.";
   BrowserList::AddObserver(this);
+
+  // Note: This should happen after all the PrefMembers have been initialized.
+  OnFloatingModePrefChanged();
 }
 
 VerticalTabStripRegionView::~VerticalTabStripRegionView() {
diff --git a/browser/ui/views/frame/vertical_tab_strip_region_view.h b/browser/ui/views/frame/vertical_tab_strip_region_view.h
index 9b556700a01f..41e0d3942eea 100644
--- a/browser/ui/views/frame/vertical_tab_strip_region_view.h
+++ b/browser/ui/views/frame/vertical_tab_strip_region_view.h
@@ -202,7 +202,6 @@ class VerticalTabStripRegionView : public views::View,
   BooleanPrefMember collapsed_pref_;
   BooleanPrefMember expanded_state_per_window_pref_;
   BooleanPrefMember floating_mode_pref_;
-  BooleanPrefMember sidebar_side_;
 
   IntegerPrefMember expanded_width_pref_;
   int expanded_width_ = 220;
@@ -229,6 +228,7 @@ class VerticalTabStripRegionView : public views::View,
       fullscreen_observation_{this};
 
   BooleanPrefMember vertical_tab_on_right_;
+  BooleanPrefMember sidebar_side_;
 
   base::WeakPtrFactory<VerticalTabStripRegionView> weak_factory_{this};
 };