src/vs/workbench/api/browser/mainThreadDocumentsAndEditors.ts/MainThreadDocumentAndEditorStateComputer/_getActiveEditorFromPanel
class MainThreadDocumentAndEditorStateComputer:	private _getActiveEditorFromPanel(): IEditor | undefined {
		const panel = this._paneCompositeService.getActivePaneComposite(ViewContainerLocation.Panel);
		if (panel instanceof AbstractTextEditor) {
			const control = panel.getControl();
			if (isCodeEditor(control)) {
				return control;
			}
		}

		return undefined;
	}