Gateway-Toolstip broken after update NW.3.20130723a.2 (2013-08-01)

After the update, tooltips in the Gateway don't show correctly any more. They have no background and so the contents is barely readable. To be more specific, the tooltips that hold crafting category level and exp information and the tooltips with item details both in a crafting category assignments listing and on a detail page for an assignment are not working correctly. Other tooltips i did not check.

I cleared all browser caches and retried but no change. I am using Firefox 17.0.7 ESR on linux.