Bug 449622 – right clicking on Get more search engines in search manager acts as a left click. r=gavin

browser/components/search/content/engineManager.xul

@@ -125,7 +125,7 @@
   </hbox>
   <hbox>
     <label id="addEngines" class="text-link" value="&addEngine.label;"
-           onclick="gEngineManagerDialog.loadAddEngines();"/>
+           onclick="if (event.button == 0) { gEngineManagerDialog.loadAddEngines(); }"/>
     <spacer flex="1"/>
   </hbox>
 </dialog>