Bug 356680 - Use hidden instead of collapsed to hide tabs

r=silver@warwickcompsoc.co.uk (James Ross)
ChatZilla Only.

extensions/irc/xul/content/chatzilla.xul

@@ -127,8 +127,8 @@
         <hbox id="view-tabs" persist="collapsed" flex="1">
           <tabs class="tabs-bottom" id="views-tbar-inner" flex="1"
               onselect="onTabSelect(event)" setfocus="false">
-            <tab collapsed="true"/> <!-- dummy tab to keep the freaking xbl from
-                                         causing an exception -->
+            <tab hidden="true"/> <!-- dummy tab to keep the freaking xbl from
+                                      causing an exception -->
           </tabs>
           <spacer id="views-tbar-spacer"/>
         </hbox>