Also in the main chatroom, when creating a private room.
Trying to invite someone produces the "you do not have permission"
pops up despite all permissions set to yes across Mchat.
It sounds like not all extension files were updated. Please disable the Sticky Footer extension, delete the extension folder via FTP and upload a fresh copy. Enable the extension and clear the board cache in the ACP.
Also update to the latest Rooms version and open a new topic in the Rooms forum if that doesn't fix the problem.
Ok disabled SF, deleted it from ext folder uploaded fresh copy, cleared cache and enabled the extension. Went to forum and SF was not showing on any page. Reverted back to old version and works fine ?
For reference, this is an issue with the Collapsible Categories extension and was already requested here.
To force mChat to be collapsed for all existing users, run this SQL query in phpMyAdmin or similar. It worked in my local tests but I can't guarantee this works in all cases. Make sure you have a backup of the users table.