[gnome-builder] symbol-tree: restrict max width of popover

[Christian Hergert <chergert src gnome org>]

commit c8c6e56f7137eec0dc0695817e08a32454f24cf0
Author: Christian Hergert <chergert redhat com>
Date:   Tue Dec 10 11:10:19 2019 -0800

    symbol-tree: restrict max width of popover
    
    We have a scrolled window, and it's fine to use. We just want
    to primarily scale with the content within reason.
    
    Related #1096

 src/plugins/symbol-tree/gbp-symbol-menu-button.ui | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/src/plugins/symbol-tree/gbp-symbol-menu-button.ui 
b/src/plugins/symbol-tree/gbp-symbol-menu-button.ui
index cc425d04a..2d8849613 100644
--- a/src/plugins/symbol-tree/gbp-symbol-menu-button.ui
+++ b/src/plugins/symbol-tree/gbp-symbol-menu-button.ui
@@ -36,6 +36,7 @@
             <property name="min-content-width">250</property>
             <property name="min-content-height">300</property>
             <property name="max-content-height">600</property>
+            <property name="max-content-width">500</property>
             <property name="visible">true</property>
             <child>
               <object class="DzlTree" id="tree">