diff --git a/demos/gtk-demo/blendmodes.ui b/demos/gtk-demo/blendmodes.ui
index e87a0a8970..5826f41d44 100644
--- a/demos/gtk-demo/blendmodes.ui
+++ b/demos/gtk-demo/blendmodes.ui
@@ -8,6 +8,10 @@
     <property name="default-height">300</property>
     <child>
       <object class="GtkGrid">
+        <property name="margin-start">12</property>
+        <property name="margin-end">12</property>
+        <property name="margin-top">12</property>
+        <property name="margin-bottom">12</property>
         <property name="row-spacing">12</property>
         <property name="column-spacing">12</property>
         <child>
diff --git a/demos/gtk-demo/dnd.c b/demos/gtk-demo/dnd.c
index 1aff3b1bcd..83e6e92359 100644
--- a/demos/gtk-demo/dnd.c
+++ b/demos/gtk-demo/dnd.c
@@ -566,7 +566,6 @@ canvas_new (void)
   canvas = gtk_fixed_new ();
   gtk_widget_set_hexpand (canvas, TRUE);
   gtk_widget_set_vexpand (canvas, TRUE);
-  gtk_widget_add_css_class (canvas, "frame");
 
   source = gtk_drag_source_new ();
   gtk_drag_source_set_actions (source, GDK_ACTION_MOVE);
@@ -764,6 +763,8 @@ do_dnd (GtkWidget *do_widget)
           y += 100;
         }
 
+      gtk_box_append (GTK_BOX (box), gtk_separator_new (GTK_ORIENTATION_HORIZONTAL));
+
       sw = gtk_scrolled_window_new ();
       gtk_scrolled_window_set_policy (GTK_SCROLLED_WINDOW (sw),
                                       GTK_POLICY_AUTOMATIC,
diff --git a/demos/gtk-demo/fontrendering.ui b/demos/gtk-demo/fontrendering.ui
index e9fcea53d5..f2551e29a5 100644
--- a/demos/gtk-demo/fontrendering.ui
+++ b/demos/gtk-demo/fontrendering.ui
@@ -198,10 +198,12 @@
             </child>
           </object>
         </child>
+        <child>
+          <object class="GtkSeparator"/>
+        </child>
         <child>
           <object class="GtkScrolledWindow">
             <property name="propagate-natural-height">1</property>
-            <property name="has-frame">1</property>
             <property name="hexpand">1</property>
             <property name="vexpand">1</property>
             <child>
diff --git a/demos/gtk-demo/panes.c b/demos/gtk-demo/panes.c
index 134d3bea97..e6312054f1 100644
--- a/demos/gtk-demo/panes.c
+++ b/demos/gtk-demo/panes.c
@@ -61,10 +61,6 @@ create_pane_options (GtkPaned    *paned,
   child2 = gtk_paned_get_end_child (paned);
 
   frame = gtk_frame_new (frame_label);
-  gtk_widget_set_margin_start (frame, 4);
-  gtk_widget_set_margin_end (frame, 4);
-  gtk_widget_set_margin_top (frame, 4);
-  gtk_widget_set_margin_bottom (frame, 4);
 
   table = gtk_grid_new ();
   gtk_frame_set_child (GTK_FRAME (frame), table);
@@ -110,6 +106,7 @@ do_panes (GtkWidget *do_widget)
   GtkWidget *vpaned;
   GtkWidget *button;
   GtkWidget *vbox;
+  GtkWidget *box;
 
   if (!window)
     {
@@ -120,33 +117,42 @@ do_panes (GtkWidget *do_widget)
 
       gtk_window_set_title (GTK_WINDOW (window), "Paned Widgets");
 
-      vbox = gtk_box_new (GTK_ORIENTATION_VERTICAL, 0);
+      vbox = gtk_box_new (GTK_ORIENTATION_VERTICAL, 8);
+      gtk_widget_set_margin_start (vbox, 8);
+      gtk_widget_set_margin_end (vbox, 8);
+      gtk_widget_set_margin_top (vbox, 8);
+      gtk_widget_set_margin_bottom (vbox, 8);
       gtk_window_set_child (GTK_WINDOW (window), vbox);
 
+      frame = gtk_frame_new (NULL);
+      gtk_box_append (GTK_BOX (vbox), frame);
+
       vpaned = gtk_paned_new (GTK_ORIENTATION_VERTICAL);
-      gtk_widget_set_margin_start (vpaned, 5);
-      gtk_widget_set_margin_end (vpaned, 5);
-      gtk_widget_set_margin_top (vpaned, 5);
-      gtk_widget_set_margin_bottom (vpaned, 5);
-      gtk_box_append (GTK_BOX (vbox), vpaned);
+      gtk_frame_set_child (GTK_FRAME (frame), vpaned);
 
       hpaned = gtk_paned_new (GTK_ORIENTATION_HORIZONTAL);
       gtk_paned_set_start_child (GTK_PANED (vpaned), hpaned);
 
-      frame = gtk_frame_new (NULL);
-      gtk_widget_set_size_request (frame, 60, 60);
-      gtk_paned_set_start_child (GTK_PANED (hpaned), frame);
+      box = gtk_box_new (GTK_ORIENTATION_VERTICAL, 0);
+      gtk_widget_set_size_request (box, 60, 60);
+      gtk_paned_set_start_child (GTK_PANED (hpaned), box);
 
       button = gtk_button_new_with_mnemonic ("_Hi there");
-      gtk_frame_set_child (GTK_FRAME (frame), button);
+      gtk_widget_set_margin_start (button, 4);
+      gtk_widget_set_margin_end (button, 4);
+      gtk_widget_set_margin_top (button, 4);
+      gtk_widget_set_margin_bottom (button, 4);
+      gtk_widget_set_hexpand (button, TRUE);
+      gtk_widget_set_vexpand (button, TRUE);
+      gtk_box_append (GTK_BOX (box), button);
 
-      frame = gtk_frame_new (NULL);
-      gtk_widget_set_size_request (frame, 80, 60);
-      gtk_paned_set_end_child (GTK_PANED (hpaned), frame);
+      box = gtk_box_new (GTK_ORIENTATION_VERTICAL, 0);
+      gtk_widget_set_size_request (box, 80, 60);
+      gtk_paned_set_end_child (GTK_PANED (hpaned), box);
 
-      frame = gtk_frame_new (NULL);
-      gtk_widget_set_size_request (frame, 60, 80);
-      gtk_paned_set_end_child (GTK_PANED (vpaned), frame);
+      box = gtk_box_new (GTK_ORIENTATION_VERTICAL, 0);
+      gtk_widget_set_size_request (box, 60, 80);
+      gtk_paned_set_end_child (GTK_PANED (vpaned), box);
 
       /* Now create toggle buttons to control sizing */