diff --git a/extensions/irc/xul/content/chatzilla.xul b/extensions/irc/xul/content/chatzilla.xul
index 4791f04d5a52..6c3a586f0701 100644
--- a/extensions/irc/xul/content/chatzilla.xul
+++ b/extensions/irc/xul/content/chatzilla.xul
@@ -125,7 +125,7 @@
               <tab collapsed="true"/> <!-- dummy tab to keep the freaking xbl from
                                            causing an exception -->
             </tabs>
-            <spacer flex="10000"/>
+            <spacer id="views-tbar-spacer"/>
           </scrollbox>
         </hbox>
       </hbox>
diff --git a/extensions/irc/xul/content/static.js b/extensions/irc/xul/content/static.js
index e5b332d4abfb..4ccbbe635aa2 100644
--- a/extensions/irc/xul/content/static.js
+++ b/extensions/irc/xul/content/static.js
@@ -2637,12 +2637,10 @@ function getTabForObject (source, create)
         tb.setAttribute("href", source.getURL());
         tb.setAttribute("name", source.unicodeName);
         tb.setAttribute("onclick", "onTabClick(event, " + id.quote() + ");");
-        tb.setAttribute("maxwidth", "250");
-        tb.setAttribute("flex", "1");
+        // This wouldn't be here if there was a supported CSS property for it.
         tb.setAttribute("crop", "center");
         tb.setAttribute("context", "context:tab");
-        tb.setAttribute("tooltip", "xul-tooltip-mode");
-
+        tb.setAttribute("tooltip", "xul-tooltip-node");
         tb.setAttribute("class", "tab-bottom view-button");
         tb.setAttribute("id", id);
         tb.setAttribute("state", "normal");
diff --git a/extensions/irc/xul/skin/chatzilla.css b/extensions/irc/xul/skin/chatzilla.css
index 6929506d8e26..b1be2bcf6daa 100644
--- a/extensions/irc/xul/skin/chatzilla.css
+++ b/extensions/irc/xul/skin/chatzilla.css
@@ -80,9 +80,15 @@ window {
     background: darkslategrey !important;
 }
 
+#views-tbar-spacer {
+    -moz-box-flex: 10000;
+}
+
 .view-button {
     /* do NOT set colour, at least not without background. :) */
     text-align: center;
+    max-width: 30ex;
+    -moz-box-flex: 1;
 }
 
 .view-button[state="current"] {