Hi, is that a bug (seems to be a bug) :
I'm trying to assign the .sql extension to the SQL file type. Whe I select "Apply" Idea complains tht there are no file extension registered to the XHTML file type. This is true, but I don't care about the XHTML file type, besides the .xhtml extension is registered for the XML file type by default and the XHTML file type has no extensions by default. So, I think it'a a bug, the workround is to register something for the XHTML file types :))).