I'm assuming the FF57 colrfultabs add-on is only half cooked at this stage. I got a popup yesterday explaining that the whole extension needed re-write to work with FF57, so I made a donation in appreciation of getting this done at some point. But as it stands I am having the same problem as everyone else it just changes the colour of FF tabs and menu bar to one colour with 'options' greyed out. A developer update here would be nice with an ETA of when we can expect things to be working. Cheers