HIG: different rules for message boxes

Change-Id: I67a5457fa2f39b1d6ab0a635d9bdf78ffa90caea

cui/uiconfig/ui/messbox.ui

@@ -3,13 +3,14 @@
   <!-- interface-requires gtk+ 3.0 -->
   <object class="GtkDialog" id="MessBox">
     <property name="can_focus">False</property>
-    <property name="border_width">6</property>
+    <property name="border_width">12</property>
+    <property name="resizable">False</property>
     <property name="type_hint">dialog</property>
     <child internal-child="vbox">
       <object class="GtkBox" id="dialog-vbox6">
         <property name="can_focus">False</property>
         <property name="orientation">vertical</property>
-        <property name="spacing">12</property>
+        <property name="spacing">24</property>
         <child internal-child="action_area">
           <object class="GtkButtonBox" id="dialog-action_area6">
             <property name="can_focus">False</property>
@@ -18,6 +19,8 @@
               <object class="GtkButton" id="mess_box_btn1">
                 <property name="visible">True</property>
                 <property name="can_focus">True</property>
+                <property name="can_default">True</property>
+                <property name="has_default">True</property>
                 <property name="receives_default">True</property>
               </object>
               <packing>
@@ -64,8 +67,7 @@
           <object class="GtkBox" id="box4">
             <property name="visible">True</property>
             <property name="can_focus">False</property>
-            <property name="border_width">6</property>
-            <property name="spacing">6</property>
+            <property name="spacing">12</property>
             <child>
               <object class="GtkImage" id="mess_box_image">
                 <property name="can_focus">False</property>