fixed missing updates to determine the number of selected cells

package.json

@@ -52,7 +52,7 @@
 				"title": "Add Tags to Selected Cells",
 				"icon": "$(add)",
 				"when": "jupyter-cell-tags.multipleCellsSelected"
-			},			
+			},
 			{
 				"command": "jupyter-cell-tags.editTagsInJSON",
 				"title": "Edit Cell Tags (JSON)",
@@ -133,7 +133,7 @@
 	},
 	"enabledApiProposals": [
 		"notebookCellExecutionState"
-	],	
+	],
 	"devDependencies": {
 		"@types/vscode": "^1.72.0",
 		"@types/glob": "^7.1.3",

src/extension.ts

@@ -8,7 +8,7 @@ import { register as registerCellTagsView } from './cellTagsTreeDataProvider';
 export function activate(context: vscode.ExtensionContext) {
 	registerCellTags(context);
 	registerCellTagsView(context);
-	
+
 	// Update context when the active editor or selection changes
 	vscode.window.onDidChangeActiveNotebookEditor(updateContext);
 	vscode.window.onDidChangeNotebookEditorSelection(updateContext);
@@ -25,7 +25,22 @@ function updateContext() {
         return;
     }
 
-    const selectionCount = editor.selections.length;
+    const selections: readonly vscode.NotebookRange[] = editor.selections; // NotebookRange[]
+    const selectedRangesCount = selections.length;
+    var total_num_selected_cells = 0;
+    selections.forEach(selection => {
+        const range = selection as vscode.NotebookRange;
+        if (!range.isEmpty) {
+            const num_selected_cells = range.end - range.start
+            total_num_selected_cells += num_selected_cells;
+        }
+    });
+    // TODO 2024-09-05 17:47: - [ ] Got num selected cells nearly working, it will always be correct to tell if 1 vs. many cells.
+    // Noticed error below, there were only 3 cells in the notebook but it returned 4 cells. I think the last index should be excluded but then it would give zero for single cell selections?
+    // Selection num ranges count: 1
+    // 	Selected cells: Start(0), End(4)
+    // Selection count: 4
+    const selectionCount = total_num_selected_cells;
     vscode.commands.executeCommand('setContext', 'jupyter-cell-tags.singleCellSelected', selectionCount === 1);
     vscode.commands.executeCommand('setContext', 'jupyter-cell-tags.multipleCellsSelected', selectionCount > 1);
 }