src/vs/workbench/contrib/notebook/browser/notebookEditorWidget.ts/NotebookEditorWidget/hasEditorFocus
class NotebookEditorWidget:	hasEditorFocus() {
		// _editorFocus is driven by the FocusTracker, which is only guaranteed to _eventually_ fire blur.
		// If we need to know whether we have focus at this instant, we need to check the DOM manually.
		this.updateEditorFocus();
		return this.editorHasDomFocus();
	}