[glade] Set the "About Dialogue" as modal

[Alberto Fanjul <albfan src gnome org>]

commit 8a18085273ea76ad33786a42d28743f03f23578a
Author: Veerasamy Sevagen <sevagenv gmail com>
Date:   Mon Jul 1 11:51:03 2019 +0000

    Set the "About Dialogue" as modal

 src/glade.glade | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/src/glade.glade b/src/glade.glade
index ade64e7f..ec1ff5d5 100644
--- a/src/glade.glade
+++ b/src/glade.glade
@@ -722,6 +722,7 @@ Author: Juan Pablo Ugarte
     <property name="can_focus">False</property>
     <property name="border_width">5</property>
     <property name="resizable">False</property>
+    <property name="modal">True</property>
     <property name="type_hint">dialog</property>
     <property name="transient_for">GladeWindow</property>
     <property name="copyright" translatable="yes">Copyright © 2001-2006 Ximian, Inc.