Thread:Extension talk:WikiEditor/Toolbar buttons missing after upgrade to 1.24

I've upgraded to 1.24 from a recent 1.23. I've also updated all the extensions to the REL1_24 branch. All works fine but now my toolbar buttons don't show, there's just an empty space on the toolbar until the 'Advanced' submenu. The buttons still seem to be working when I click on the empty spaces. I found a reference to the same problem on this page and I've updated my MediaWiki:Common to be the same as the one on Wikipedia but that doesn't seem to fix the issue. Any idea what could be the problem?