Fix top bar visibility not picking up settings overrides (#6833) (#6836)

* Make 'visible' enum type and pick up both default and user
      settings.

packages/application-extension/schema/top.json

@@ -18,10 +18,11 @@
   },
   "properties": {
     "visible": {
-      "type": "boolean",
+      "type": "string",
+      "enum": ["yes", "no", "automatic"],
       "title": "Top Bar Visibility",
-      "description": "Whether to show the top bar or not",
-      "default": true
+      "description": "Whether to show the top bar or not, yes for always showing, no for always not showing, automatic for adjusting to screen size",
+      "default": "automatic"
     }
   },
   "additionalProperties": false,

packages/application-extension/src/index.ts

@@ -482,22 +482,29 @@ const topVisibility: JupyterFrontEndPlugin<void> = {
       execute: () => {
         top.setHidden(top.isVisible);
         if (settingRegistry) {
-          void settingRegistry.set(pluginId, 'visible', top.isVisible);
+          void settingRegistry.set(
+            pluginId,
+            'visible',
+            top.isVisible ? 'yes' : 'no'
+          );
         }
       },
       isToggled: () => top.isVisible,
     });
 
-    let settingsOverride = false;
+    let adjustToScreen = false;
 
     if (settingRegistry) {
       const loadSettings = settingRegistry.load(pluginId);
       const updateSettings = (settings: ISettingRegistry.ISettings): void => {
-        const visible = settings.get('visible').composite;
+        // 'visible' property from user preferences or default settings
+        let visible = settings.get('visible').composite;
         if (settings.user.visible !== undefined) {
-          settingsOverride = true;
-          top.setHidden(!visible);
+          visible = settings.user.visible;
         }
+        top.setHidden(visible === 'no');
+        // adjust to screen from user preferences or default settings
+        adjustToScreen = visible === 'automatic';
       };
 
       Promise.all([loadSettings, app.restored])
@@ -517,7 +524,7 @@ const topVisibility: JupyterFrontEndPlugin<void> = {
     }
 
     const onChanged = (): void => {
-      if (settingsOverride) {
+      if (!adjustToScreen) {
         return;
       }
       if (app.format === 'desktop') {