[smuxi: 21/26] Frontend-GNOME: fix NRE thrown in ChatTreeView.ApplyConfig()

[Mirco M. M. Bauer <mmmbauer src gnome org>]

commit c054d4de868c23533b222fae05f668537ba5439f
Author: Mirco Bauer <meebey meebey net>
Date:   Thu Oct 8 22:24:20 2015 +0200

    Frontend-GNOME: fix NRE thrown in ChatTreeView.ApplyConfig()
    
    When connecting a newer frontend to an older engine (via smuxi-server) it will
    throw a NRE in ChatTreeView.ApplyConfig() as the hashtable returns null for the
    unknown key and that throws a NullReferenceException for booleans.
    
    This regression was introduced in dfacd123b5d6138c7d9614a596111efce280e207.

 src/Frontend-GNOME/Views/ChatTreeView.cs |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/Frontend-GNOME/Views/ChatTreeView.cs b/src/Frontend-GNOME/Views/ChatTreeView.cs
index d2a72f7..2427a69 100644
--- a/src/Frontend-GNOME/Views/ChatTreeView.cs
+++ b/src/Frontend-GNOME/Views/ChatTreeView.cs
@@ -217,7 +217,7 @@ namespace Smuxi.Frontend.Gnome
             }
             ModifyFont(ThemeSettings.FontDescription);
 
-            ActivityColumn.Visible = (bool) config["Interface/ShowActivityCounter"];
+            ActivityColumn.Visible = (bool?) config["Interface/ShowActivityCounter"] ?? true;
         }
 
         protected virtual void RenderChatViewIcon(Gtk.TreeViewColumn column,