Hi Lukas
It could be down to the browser too, you might find if you patch later on that with 731 some issues are introduced with IE, especially with the higher versions so always keep a check on the wiki page I mentioned in the earlier reply as invariably the latest rendering notes fix it. 731 was quite buggy with IE compatibility across all the applications such as E-Rec and FI-TV and elsewhere in ESS.
good luck!
Sally