src/vs/workbench/api/browser/mainThreadDocumentsAndEditors.ts/MainThreadDocumentAndEditorStateComputer/_getActiveEditorFromPanel
class MainThreadDocumentAndEditorStateComputer:	private _getActiveEditorFromPanel(): IEditor | undefined {
		const panel = this._panelService.getActivePanel();
		if (panel instanceof BaseTextEditor && isCodeEditor(panel.getControl())) {
			return panel.getControl();
		} else {
			return undefined;
		}
	}