diff --git a/gui/wxpython/dbmgr/base.py b/gui/wxpython/dbmgr/base.py
index 9a13930db5c..7085eff58ed 100644
--- a/gui/wxpython/dbmgr/base.py
+++ b/gui/wxpython/dbmgr/base.py
@@ -1033,7 +1033,7 @@ def DeletePage(self, layer):
         del self.layerPage[layer]
 
         if self.GetSelection() >= 0:
-            self.selLayer = self.layers[self.GetSelection()]
+            self.selLayer = self.layers[-1]
         else:
             self.selLayer = None
 
@@ -1365,6 +1365,9 @@ def OnSqlQuerySizeWrap(self, layer):
     def OnSqlQuerySize(self, event, layer):
         """Adapts SQL Query Simple tab on current width"""
 
+        if layer not in self.layers:
+            return
+
         sqlNtb = event.GetEventObject()
         if not self.sqlBestSize:
             self.sqlBestSize = sqlNtb.GetBestSize()
diff --git a/gui/wxpython/gui_core/widgets.py b/gui/wxpython/gui_core/widgets.py
index 5ba4b3b125d..cf0c7d9d089 100644
--- a/gui/wxpython/gui_core/widgets.py
+++ b/gui/wxpython/gui_core/widgets.py
@@ -133,7 +133,17 @@ def BindPageChanged(self):
         self.widget.Bind(wx.EVT_NOTEBOOK_PAGE_CHANGED, self.OnRemoveHighlight)
 
     def AddPage(self, *args, **kwargs):
-        """Add a new page"""
+        """Add a new page
+
+        :param str name: use this param if notebooks has ability to
+                         change position and then you must use page name
+                         param arg to correctly delete notebook page.
+                         If you do not use this parameter, make sure that
+                         the notebooks does not have the ability to change
+                         position, because in that case the deletion of
+                         the page based on the position index would not
+                         work correctly.
+        """
         if "name" in kwargs:
             self.notebookPages[kwargs["name"]] = kwargs["page"]
             del kwargs["name"]
@@ -141,7 +151,17 @@ def AddPage(self, *args, **kwargs):
         self.classObject.AddPage(self.widget, *args, **kwargs)
 
     def InsertPage(self, *args, **kwargs):
-        """Insert a new page"""
+        """Insert a new page
+
+        :param str name: use this param if notebooks has ability to
+                         change position and then you must use page name
+                         param arg to correctly delete notebook page.
+                         If you do not use this parameter, make sure that
+                         the notebooks does not have the ability to change
+                         position, because in that case the deletion of
+                         the page based on the position index would not
+                         work correctly.
+        """
         if "name" in kwargs:
             self.notebookPages[kwargs["name"]] = kwargs["page"]
             del kwargs["name"]
@@ -156,8 +176,9 @@ def InsertPage(self, *args, **kwargs):
     def DeletePage(self, page):
         """Delete page
 
-        :param page: name
-        :return: True if page was deleted, False if not exists
+        :param str|int page: page name or page index position
+
+        :return bool: True if page was deleted, False if not exists
         """
         delPageIndex = self.GetPageIndexByName(page)
         if delPageIndex != -1:
@@ -214,8 +235,12 @@ def RemoveHighlight(self, page):
     def GetPageIndexByName(self, page):
         """Get notebook page index
 
-        :param page: name
+        :param str|int page: page name or page index position
+
+        :return int: page index
         """
+        if not self.notebookPages:
+            return page
         if page not in self.notebookPages:
             return -1
         for pageIndex in range(self.classObject.GetPageCount(self.widget)):
@@ -258,8 +283,12 @@ def BindPageChanged(self):
     def GetPageIndexByName(self, page):
         """Get notebook page index
 
-        :param page: name
+        :param str|int page: page name or page index position
+
+        :return int: page index
         """
+        if not self.notebookPages:
+            return page
         if page not in self.notebookPages:
             return -1