From time to time the Default appearance turns on w/o me doing anything special. Just start FF as usual and pop, there goes that ugly (sorry, but it is) hospital-like bluish appearance. I have another appearance enabled when this happens. At the same time button "Translate" disappears from my toolbar and I need to place it back there again. Other custom buttons (e.g. resurrect) do not disappear. I have not noticed anything particular preceding this except for perhaps one thing: add-on updates. It might be happening always after an add-on update. Unfortunately updates do not ask for update confirmation (why? sigh) so the only way for me to check this is to set them to manual and then try not to forget to update them :-/ Obviously this will probably not tell me if any/what particular add-on is the cause (sigh, sigh, sigh), but I'll see. Any ideas, pls? Karel