''locking this thread as duplicate, continue at [https://support.mozilla.org/questions/1217422]'' Web browser, like any other program, has its logic. Main frame on top. Permanent features below. Less permanent more below. Temporary things in the last line- like opened sites, etc. Just HUMAN LOGICAL ORDER. When some stupid and evidently idiot developer was allowed to make Firefox look like a copy of Chrome- he should be banned for ever from Mozilla. We had to install addon like Classic Theme Restorer to have our Firefox like always. Now instead of simple browser option or addon- we have to mess up with "css" files to make Firefox look logical and usable. Is that idiot who wanted to destroy Firefox base of users still working in Mozilla?