Editing teiid importer connection url can't be finished

I have Teiid importer connection set up without authentication and when I try to edit its URL I get an error message "The User Name cannot be empty" (the same with password) but my connection doesn't need authentication, so I don't have any username or password. 'OK' button is disabled.

JBDS 7.1.1.GA + TeiidDesigner 8.3.2