Modal window fixes

ubl-settings-diskquota.glade

@@ -2721,6 +2721,8 @@ translated and supported by community.</property>
   </object>
   <object class="GtkWindow" id="tableUserGroupWindow">
     <property name="can-focus">False</property>
+    <property name="resizable">False</property>
+    <property name="modal">True</property>
     <property name="default-width">250</property>
     <property name="default-height">400</property>
     <property name="icon-name">com.ublinux.ubl-settings-diskquota</property>