Notebook chat editing enhancements. (microsoft#205799)

* Notebook chat editing enhancements.

* hide cell chat actions from f1.

Author: rebornix

src/vs/workbench/contrib/notebook/browser/controller/chat/cellChatActions.ts

@@ -382,6 +382,7 @@ registerAction2(class extends NotebookAction {
 						}
 					]
 				},
+				f1: false,
 				menu: [
 					{
 						id: MenuId.NotebookCellBetween,
@@ -454,6 +455,7 @@ registerAction2(class extends NotebookAction {
 					original: '$(sparkle) Generate',
 				},
 				tooltip: localize('notebookActions.menu.insertCodeCellWithChat.tooltip', "Generate Code Cell with Chat"),
+				f1: false,
 				menu: [
 					{
 						id: MenuId.NotebookCellListTop,

src/vs/workbench/contrib/notebook/browser/controller/chat/notebookChatController.ts

@@ -369,7 +369,7 @@ export class NotebookChatController extends Disposable implements INotebookEdito
 				const cellTop = this._notebookEditor.getAbsoluteTopOfElement(previousCell);
 				const cellHeight = this._notebookEditor.getHeightOfElement(previousCell);
 
-				this._notebookEditor.revealOffsetInCenterIfOutsideViewport(cellTop + cellHeight);
+				this._notebookEditor.revealOffsetInCenterIfOutsideViewport(cellTop + cellHeight + 48 /** center of the dialog */);
 			}
 		}
 	}
@@ -412,6 +412,12 @@ export class NotebookChatController extends Disposable implements INotebookEdito
 			return;
 		}
 
+		if (this._widget.editingCell && this._widget.editingCell.textBuffer.getLength() > 0) {
+			// it already contains some text, clear it
+			const ref = await this._widget.editingCell.resolveTextModel();
+			ref.setValue('');
+		}
+
 		const editingCellIndex = this._widget.editingCell ? this._notebookEditor.getCellIndex(this._widget.editingCell) : undefined;
 		if (editingCellIndex !== undefined) {
 			this._notebookEditor.setSelections([{