[gnome-control-center] shell: Synchronize the right panel width

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit 4c813fa1d8c985dc6c39aaa2adbcad30d9ec7540
Author: Adrien Plazas <kekun plazas laposte net>
Date:   Tue Nov 27 16:10:32 2018 +0100

    shell: Synchronize the right panel width
    
    This will help the right panel to behave properly with leaflets, as we
    are going to introduce some in some following commits.

 shell/cc-window.ui | 9 +++++++++
 1 file changed, 9 insertions(+)
---
diff --git a/shell/cc-window.ui b/shell/cc-window.ui
index a9e39b897..33de23797 100644
--- a/shell/cc-window.ui
+++ b/shell/cc-window.ui
@@ -245,6 +245,15 @@
     </widgets>
   </object>
 
+  <!-- Synchronize right header and panel -->
+  <object class="GtkSizeGroup">
+    <property name="mode">horizontal</property>
+    <widgets>
+      <widget name="panel_headerbar"/>
+      <widget name="stack"/>
+    </widgets>
+  </object>
+
   <!-- Warning dialog for development builds -->
   <object class="GtkMessageDialog" id="development_warning_dialog">
     <property name="message-type">warning</property>