fix #119205.

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

@@ -362,6 +362,7 @@ export class ListView<T> implements ISpliceable<T>, IDisposable {
 	updateOptions(options: IListViewOptionsUpdate) {
 		if (options.additionalScrollHeight !== undefined) {
 			this.additionalScrollHeight = options.additionalScrollHeight;
+			this.scrollableElement.setScrollDimensions({ scrollHeight: this.scrollHeight });
 		}
 
 		if (options.smoothScrolling !== undefined) {

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

@@ -694,6 +694,7 @@ export interface INotebookCellList {
 	domFocus(): void;
 	setCellSelection(element: ICellViewModel, range: Range): void;
 	style(styles: IListStyles): void;
+	getRenderHeight(): number;
 	updateOptions(options: IListOptions<ICellViewModel>): void;
 	layout(height?: number, width?: number): void;
 	dispose(): void;

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

@@ -1428,8 +1428,15 @@ export class NotebookEditorWidget extends Disposable implements INotebookEditor
 
 		this._dimension = new DOM.Dimension(dimension.width, dimension.height);
 		DOM.size(this._body, dimension.width, dimension.height - (this._useGlobalToolbar ? /** Toolbar height */ 26 : 0));
-		this._list.updateOptions({ additionalScrollHeight: this._scrollBeyondLastLine ? dimension.height - SCROLLABLE_ELEMENT_PADDING_TOP : SCROLLABLE_ELEMENT_PADDING_TOP });
-		this._list.layout(dimension.height - SCROLLABLE_ELEMENT_PADDING_TOP, dimension.width);
+		if (this._list.getRenderHeight() < dimension.height - SCROLLABLE_ELEMENT_PADDING_TOP) {
+			// the new dimension is larger than the list viewport, update its additional height first, otherwise the list view will move down a bit (as the `scrollBottom` will move down)
+			this._list.updateOptions({ additionalScrollHeight: this._scrollBeyondLastLine ? Math.max(0, (dimension.height - SCROLLABLE_ELEMENT_PADDING_TOP - 50)) : SCROLLABLE_ELEMENT_PADDING_TOP });
+			this._list.layout(dimension.height - SCROLLABLE_ELEMENT_PADDING_TOP, dimension.width);
+		} else {
+			// the new dimension is smaller than the list viewport, if we update the additional height, the `scrollBottom` will move up, which moves the whole list view upwards a bit. So we run a layout first.
+			this._list.layout(dimension.height - SCROLLABLE_ELEMENT_PADDING_TOP, dimension.width);
+			this._list.updateOptions({ additionalScrollHeight: this._scrollBeyondLastLine ? Math.max(0, (dimension.height - SCROLLABLE_ELEMENT_PADDING_TOP - 50)) : SCROLLABLE_ELEMENT_PADDING_TOP });
+		}
 
 		this._overlayContainer.style.visibility = 'visible';
 		this._overlayContainer.style.display = 'block';

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

@@ -1246,6 +1246,10 @@ export class NotebookCellList extends WorkbenchList<CellViewModel> implements ID
 		}
 	}
 
+	getRenderHeight() {
+		return this.view.renderHeight;
+	}
+
 	layout(height?: number, width?: number): void {
 		this._isInLayout = true;
 		super.layout(height, width);