diff --git a/js/dbusServices/extensions/css/application.css b/js/dbusServices/extensions/css/application.css
index 1acbf36c8..fb7c47556 100644
--- a/js/dbusServices/extensions/css/application.css
+++ b/js/dbusServices/extensions/css/application.css
@@ -1,4 +1,4 @@
-.expander-frame > * { border-top-width: 0; }
+.expanded { border: 0 solid @borders; border-bottom-width: 1px; }
 .expander-toolbar {
   border: 0 solid @borders;
   border-top-width: 1px;
diff --git a/js/dbusServices/extensions/extensionsService.js b/js/dbusServices/extensions/extensionsService.js
index 456ca6ba7..34107cdb3 100644
--- a/js/dbusServices/extensions/extensionsService.js
+++ b/js/dbusServices/extensions/extensionsService.js
@@ -192,7 +192,10 @@ var ExtensionPrefsDialog = GObject.registerClass({
             this._expanderArrow.icon_name = this._revealer.reveal_child
                 ? 'pan-down-symbolic'
                 : 'pan-end-symbolic';
+            this._syncExpandedStyle();
         });
+        this._revealer.connect('notify::child-revealed',
+            () => this._syncExpandedStyle());
 
         try {
             ExtensionUtils.installImporter(extension);
@@ -211,6 +214,13 @@ var ExtensionPrefsDialog = GObject.registerClass({
         }
     }
 
+    _syncExpandedStyle() {
+        if (this._revealer.reveal_child)
+            this._expander.get_style_context().add_class('expanded');
+        else if (!this._revealer.child_revealed)
+            this._expander.get_style_context().remove_class('expanded');
+    }
+
     _setError(exc) {
         this._errorView.buffer.text = `${exc}\n\nStack trace:\n`;
         // Indent stack trace.
diff --git a/js/dbusServices/extensions/ui/extension-prefs-dialog.ui b/js/dbusServices/extensions/ui/extension-prefs-dialog.ui
index 020bc4462..9e51e3c58 100644
--- a/js/dbusServices/extensions/ui/extension-prefs-dialog.ui
+++ b/js/dbusServices/extensions/ui/extension-prefs-dialog.ui
@@ -53,16 +53,16 @@
                       </object>
                     </child>
                     <child>
-                      <object class="GtkBox">
+                      <object class="GtkFrame">
                         <property name="visible">True</property>
-                        <property name="orientation">vertical</property>
                         <property name="margin-top">12</property>
                         <child>
-                          <object class="GtkFrame" id="expander">
+                          <object class="GtkBox">
                             <property name="visible">True</property>
                             <property name="hexpand">True</property>
+                            <property name="orientation">vertical</property>
                             <child>
-                              <object class="GtkEventBox">
+                              <object class="GtkEventBox" id="expander">
                                 <property name="visible">True</property>
                                 <child>
                                   <object class="GtkBox">
@@ -88,17 +88,9 @@
                                 </child>
                               </object>
                             </child>
-                          </object>
-                        </child>
-                        <child>
-                          <object class="GtkRevealer" id="revealer">
-                            <property name="visible">True</property>
                             <child>
-                              <object class="GtkFrame">
+                              <object class="GtkRevealer" id="revealer">
                                 <property name="visible">True</property>
-                                <style>
-                                  <class name="expander-frame"/>
-                                </style>
                                 <child>
                                   <object class="GtkBox">
                                     <property name="visible">True</property>