list view resize: anchored element will keep its visual position

src/vs/base/browser/ui/list/listView.ts

@@ -279,14 +279,20 @@ export class ListView<T> implements ISpliceable<T>, IDisposable {
 		this.scrollableElement.triggerScrollFromMouseWheelEvent(browserEvent);
 	}
 
-	updateElementHeight(index: number, size: number): void {
+	updateElementHeight(index: number, size: number, anchorIndex: number | null): void {
 		if (this.items[index].size === size) {
 			return;
 		}
 
 		const lastRenderRange = this.getRenderRange(this.lastRenderTop, this.lastRenderHeight);
 
-		const heightDiff = index < lastRenderRange.start ? size - this.items[index].size : 0;
+		const heightDiff =
+			(anchorIndex !== null && anchorIndex > index && anchorIndex <= lastRenderRange.end)
+				? size - this.items[index].size // Element at anchor index will keep its visual position
+				: index < lastRenderRange.start
+					? size - this.items[index].size
+					: 0;
+
 		this.rangeMap.splice(index, 1, [{ size: size }]);
 		this.items[index].size = size;
 

src/vs/base/browser/ui/list/listWidget.ts

@@ -1314,7 +1314,7 @@ export class List<T> implements ISpliceable<T>, IDisposable {
 	}
 
 	updateElementHeight(index: number, size: number): void {
-		this.view.updateElementHeight(index, size);
+		this.view.updateElementHeight(index, size, null);
 	}
 
 	rerender(): void {

src/vs/workbench/contrib/notebook/browser/contrib/notebookActions.ts

@@ -6,7 +6,7 @@
 import { KeyCode, KeyMod } from 'vs/base/common/keyCodes';
 import { MenuRegistry, MenuId, Action2, registerAction2 } from 'vs/platform/actions/common/actions';
 import { ContextKeyExpr } from 'vs/platform/contextkey/common/contextkey';
-import { InputFocusedContext, InputFocusedContextKey } from 'vs/platform/contextkey/common/contextkeys';
+import { InputFocusedContext, InputFocusedContextKey, IsDevelopmentContext } from 'vs/platform/contextkey/common/contextkeys';
 import { KeybindingWeight } from 'vs/platform/keybinding/common/keybindingsRegistry';
 import { INotebookService } from 'vs/workbench/contrib/notebook/browser/notebookService';
 import { IEditorService } from 'vs/workbench/services/editor/common/editorService';
@@ -470,3 +470,38 @@ registerAction2(class extends Action2 {
 		editor.focusNotebookCell(newCell, true);
 	}
 });
+
+registerAction2(class extends Action2 {
+	constructor() {
+		super({
+			id: 'workbench.action.notebook.testResize',
+			title: 'Notebook Test Cell Resize',
+			keybinding: {
+				when: IsDevelopmentContext,
+				primary: undefined,
+				weight: KeybindingWeight.WorkbenchContrib
+			},
+			f1: true
+		});
+	}
+
+	async run(accessor: ServicesAccessor): Promise<void> {
+		const editorService = accessor.get(IEditorService);
+		const resource = editorService.activeEditor?.resource;
+		if (!resource) {
+			return;
+		}
+
+		const editor = getActiveNotebookEditor(editorService);
+		if (!editor) {
+			return;
+		}
+
+		const cells = editor.viewModel?.viewCells;
+
+		if (cells && cells.length) {
+			const firstCell = cells[0];
+			editor.layoutNotebookCell(firstCell, 400);
+		}
+	}
+});

src/vs/workbench/contrib/notebook/browser/view/notebookCellList.ts

@@ -118,7 +118,8 @@ export class NotebookCellList extends WorkbenchList<CellViewModel> implements ID
 	}
 
 	updateElementHeight(index: number, size: number): void {
-		this.view.updateElementHeight(index, size);
+		const focused = this.getFocus();
+		this.view.updateElementHeight(index, size, focused.length ? focused[0] : null);
 	}
 
 	// override