diff --git a/packages/apputils/src/thememanager.ts b/packages/apputils/src/thememanager.ts
index 15c52d8e1702..1f744227b338 100644
--- a/packages/apputils/src/thememanager.ts
+++ b/packages/apputils/src/thememanager.ts
@@ -217,8 +217,8 @@ export class ThemeManager implements IThemeManager {
   /**
    * Toggle the `theme-scrollbbars` setting.
    */
-  toggleThemeScrollbars(): void {
-    this._settings.set(
+  toggleThemeScrollbars(): Promise<void> {
+    return this._settings.set(
       'theme-scrollbars',
       !this._settings.composite['theme-scrollbars']
     );
diff --git a/packages/statusbar/src/defaults/kernelStatus.tsx b/packages/statusbar/src/defaults/kernelStatus.tsx
index 23a6f0f59b80..0d76fa145d87 100644
--- a/packages/statusbar/src/defaults/kernelStatus.tsx
+++ b/packages/statusbar/src/defaults/kernelStatus.tsx
@@ -181,12 +181,17 @@ export namespace KernelStatus {
       const oldState = this._getAllState();
       const { newValue } = change;
       if (newValue !== null) {
-        newValue.getSpec().then(spec => {
-          // sync setting of status and display name
-          this._kernelStatus = newValue.status;
-          this._kernelName = spec.display_name;
-          this._triggerChange(oldState, this._getAllState());
-        });
+        newValue
+          .getSpec()
+          .then(spec => {
+            // sync setting of status and display name
+            this._kernelStatus = newValue.status;
+            this._kernelName = spec.display_name;
+            this._triggerChange(oldState, this._getAllState());
+          })
+          .catch(err => {
+            throw err;
+          });
       } else {
         this._kernelStatus = 'unknown';
         this._kernelName = 'unknown';