diff --git a/qe.ipynb b/qe.ipynb
index 7ae6eb778..cfc21bccd 100644
--- a/qe.ipynb
+++ b/qe.ipynb
@@ -56,9 +56,8 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "from IPython.display import display\n",
-    "\n",
     "from aiidalab_qe.app.wrapper import AppWrapperContoller, AppWrapperModel, AppWrapperView\n",
+    "from IPython.display import display\n",
     "\n",
     "model = AppWrapperModel()\n",
     "view = AppWrapperView()\n",
@@ -75,12 +74,12 @@
    "source": [
     "import urllib.parse as urlparse\n",
     "\n",
+    "from aiidalab_qe.app.main import App\n",
+    "\n",
     "from aiidalab_widgets_base.bug_report import (\n",
     "    install_create_github_issue_exception_handler,\n",
     ")\n",
     "\n",
-    "from aiidalab_qe.app.main import App\n",
-    "\n",
     "install_create_github_issue_exception_handler(\n",
     "    view.output,\n",
     "    url=\"https://github.com/aiidalab/aiidalab-qe/issues/new\",\n",
diff --git a/src/aiidalab_qe/app/wrapper.py b/src/aiidalab_qe/app/wrapper.py
index 999f9aca7..c472c7ee8 100644
--- a/src/aiidalab_qe/app/wrapper.py
+++ b/src/aiidalab_qe/app/wrapper.py
@@ -11,7 +11,7 @@ def without_triggering(toggle: str):
     def decorator(func):
         def wrapper(self, change: dict):
             """Toggle off other button without triggering its callback."""
-            view: AppWrapperView = getattr(self, "_view")
+            view: AppWrapperView = self._view
             button: ipw.ToggleButton = getattr(view, toggle)
             callback = getattr(self, f"_on_{toggle}")
             button.unobserve(callback, "value")