I think I have really fixed the master_categories_id problems now. It at least works a lot better now than with any previous version. It now also allows to quickly fix multiple invalid linked categories (and if you don't know what an invalid category is, try a search on these forums for "+invalid +master_categories_id" ;-)).

Probably I will upload after this weekend (and probably I will fix the hardcoded color issues before upload). Or maybe sooner, if all tests run well and time permits...