fix #105901.

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

@@ -23,7 +23,7 @@ import { IQuickInputService, IQuickPickItem, QuickPickInput } from 'vs/platform/
 import { CATEGORIES } from 'vs/workbench/common/actions';
 import { BaseCellRenderTemplate, CellEditState, CellFocusMode, EXPAND_CELL_CONTENT_COMMAND_ID, ICellViewModel, INotebookEditor, NOTEBOOK_CELL_EDITABLE, NOTEBOOK_CELL_EDITOR_FOCUSED, NOTEBOOK_CELL_HAS_OUTPUTS, NOTEBOOK_CELL_INPUT_COLLAPSED, NOTEBOOK_CELL_LIST_FOCUSED, NOTEBOOK_CELL_MARKDOWN_EDIT_MODE, NOTEBOOK_CELL_OUTPUT_COLLAPSED, NOTEBOOK_CELL_TYPE, NOTEBOOK_EDITOR_EDITABLE, NOTEBOOK_EDITOR_EXECUTING_NOTEBOOK, NOTEBOOK_EDITOR_FOCUSED, NOTEBOOK_EDITOR_RUNNABLE, NOTEBOOK_IS_ACTIVE_EDITOR, NOTEBOOK_OUTPUT_FOCUSED } from 'vs/workbench/contrib/notebook/browser/notebookBrowser';
 import { CellViewModel } from 'vs/workbench/contrib/notebook/browser/viewModel/notebookViewModel';
-import { CellEditType, CellKind, ICellEditOperation, ICellRange, isDocumentExcludePattern, NotebookCellMetadata, NotebookCellRunState, NOTEBOOK_EDITOR_CURSOR_BOUNDARY, TransientMetadata } from 'vs/workbench/contrib/notebook/common/notebookCommon';
+import { CellEditType, CellKind, ICellEditOperation, ICellRange, isDocumentExcludePattern, NotebookCellMetadata, NotebookCellRunState, NOTEBOOK_EDITOR_CURSOR_BEGIN_END, NOTEBOOK_EDITOR_CURSOR_BOUNDARY, TransientMetadata } from 'vs/workbench/contrib/notebook/common/notebookCommon';
 import { INotebookService } from 'vs/workbench/contrib/notebook/common/notebookService';
 import { IEditorGroupsService } from 'vs/workbench/services/editor/common/editorGroupsService';
 import { IEditorService } from 'vs/workbench/services/editor/common/editorService';
@@ -1609,7 +1609,7 @@ registerAction2(class extends NotebookCellAction {
 				title: localize('notebookActions.splitCell', "Split Cell"),
 				menu: {
 					id: MenuId.NotebookCellTitle,
-					when: ContextKeyExpr.and(NOTEBOOK_EDITOR_FOCUSED, NOTEBOOK_EDITOR_EDITABLE, NOTEBOOK_CELL_EDITABLE, NOTEBOOK_CELL_EDITOR_FOCUSED),
+					when: ContextKeyExpr.and(NOTEBOOK_EDITOR_FOCUSED, NOTEBOOK_EDITOR_EDITABLE, NOTEBOOK_CELL_EDITABLE, NOTEBOOK_CELL_EDITOR_FOCUSED, NOTEBOOK_EDITOR_CURSOR_BEGIN_END.toNegated()),
 					order: CellToolbarOrder.SplitCell,
 					group: CELL_TITLE_CELL_GROUP_ID,
 					// alt: {
@@ -1619,7 +1619,7 @@ registerAction2(class extends NotebookCellAction {
 				},
 				icon: { id: 'codicon/split-vertical' },
 				keybinding: {
-					when: ContextKeyExpr.and(NOTEBOOK_EDITOR_FOCUSED, NOTEBOOK_EDITOR_EDITABLE, NOTEBOOK_CELL_EDITABLE, NOTEBOOK_CELL_EDITOR_FOCUSED),
+					when: ContextKeyExpr.and(NOTEBOOK_EDITOR_FOCUSED, NOTEBOOK_EDITOR_EDITABLE, NOTEBOOK_CELL_EDITABLE, NOTEBOOK_CELL_EDITOR_FOCUSED, NOTEBOOK_EDITOR_CURSOR_BEGIN_END.toNegated()),
 					primary: KeyChord(KeyMod.CtrlCmd | KeyCode.KEY_K, KeyMod.CtrlCmd | KeyMod.Shift | KeyCode.US_BACKSLASH),
 					weight: KeybindingWeight.WorkbenchContrib
 				},

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

@@ -21,7 +21,7 @@ import { IListService, IWorkbenchListOptions, WorkbenchList } from 'vs/platform/
 import { IThemeService } from 'vs/platform/theme/common/themeService';
 import { CellRevealPosition, CellRevealType, CursorAtBoundary, getVisibleCells, ICellViewModel, INotebookCellList, reduceCellRanges, CellEditState, CellFocusMode, BaseCellRenderTemplate, NOTEBOOK_CELL_LIST_FOCUSED, cellRangesEqual } from 'vs/workbench/contrib/notebook/browser/notebookBrowser';
 import { CellViewModel, NotebookViewModel } from 'vs/workbench/contrib/notebook/browser/viewModel/notebookViewModel';
-import { diff, IProcessedOutput, NOTEBOOK_EDITOR_CURSOR_BOUNDARY, CellKind, ICellRange } from 'vs/workbench/contrib/notebook/common/notebookCommon';
+import { diff, IProcessedOutput, NOTEBOOK_EDITOR_CURSOR_BOUNDARY, CellKind, ICellRange, NOTEBOOK_EDITOR_CURSOR_BEGIN_END } from 'vs/workbench/contrib/notebook/common/notebookCommon';
 import { clamp } from 'vs/base/common/numbers';
 import { SCROLLABLE_ELEMENT_PADDING_TOP } from 'vs/workbench/contrib/notebook/browser/constants';
 
@@ -115,6 +115,9 @@ export class NotebookCellList extends WorkbenchList<CellViewModel> implements ID
 		const notebookEditorCursorAtBoundaryContext = NOTEBOOK_EDITOR_CURSOR_BOUNDARY.bindTo(contextKeyService);
 		notebookEditorCursorAtBoundaryContext.set('none');
 
+		const notebookEditorCursorAtBeginEndContext = NOTEBOOK_EDITOR_CURSOR_BEGIN_END.bindTo(contextKeyService);
+		notebookEditorCursorAtBeginEndContext.set(false);
+
 		let cursorSelectionListener: IDisposable | null = null;
 		let textEditorAttachListener: IDisposable | null = null;
 
@@ -133,6 +136,13 @@ export class NotebookCellList extends WorkbenchList<CellViewModel> implements ID
 					notebookEditorCursorAtBoundaryContext.set('none');
 					break;
 			}
+
+			if (element.cursorAtBeginEnd()) {
+				notebookEditorCursorAtBeginEndContext.set(true);
+			} else {
+				notebookEditorCursorAtBeginEndContext.set(false);
+			}
+
 			return;
 		};
 

src/vs/workbench/contrib/notebook/browser/viewModel/baseCellViewModel.ts

@@ -352,6 +352,34 @@ export abstract class BaseCellViewModel extends Disposable {
 		return this._textEditor.getTopForPosition(line, column) + EDITOR_TOP_PADDING;
 	}
 
+	cursorAtBeginEnd(): boolean {
+		if (!this._textEditor) {
+			return false;
+		}
+
+		if (!this.textModel) {
+			return false;
+		}
+
+		// only validate primary cursor
+		const selection = this._textEditor.getSelection();
+
+		// only validate empty cursor
+		if (!selection || !selection.isEmpty()) {
+			return false;
+		}
+
+		if (selection.startLineNumber === 1 && selection.startColumn === 1) {
+			return true;
+		}
+
+		if (selection.startLineNumber === this._textModel?.getLineCount() && selection.startColumn === this._textModel?.getLineMaxColumn(selection.startLineNumber)) {
+			return true;
+		}
+
+		return false;
+	}
+
 	cursorAtBoundary(): CursorAtBoundary {
 		if (!this._textEditor) {
 			return CursorAtBoundary.None;

src/vs/workbench/contrib/notebook/common/notebookCommon.ts

@@ -681,6 +681,7 @@ export interface ICellEditorViewState {
 }
 
 export const NOTEBOOK_EDITOR_CURSOR_BOUNDARY = new RawContextKey<'none' | 'top' | 'bottom' | 'both'>('notebookEditorCursorAtBoundary', 'none');
+export const NOTEBOOK_EDITOR_CURSOR_BEGIN_END = new RawContextKey<boolean>('notebookEditorCursorAtEditorBeginEnd', false);
 
 
 export interface INotebookEditorModel extends IEditorModel {