1. The new tab button some times goes from it's intended place (next to the last tab) to all the way to the right side even with a mile of empty space behind it. When it does that, only closing and opening firefox will "fix" it, moving it on the customization screen doesn't seem to work. 2. The tab list button (the one that is usually next to the new tab button) doesn't appear at all to me unless I move it to the left side of the tabs. 3. When not maximized there's a space behind the first tab that doesn't seem to really do anything, can't put anything there on the customization screen, it's pretty irrelevant. I'm not using any tab addons. I even tried a completely clean install since I wanted to do it anyway for 57. Have some pics of it: Not Maximized, Customization active, you can see that the tab list button is there, both it and the new tab buttons are way to the right side of the tabs and you can see the empty space I talked about on 3. is there to the left. https://i.imgur.com/FsQarqC.jpg Not Maximized, Customization not active, you can see that the tab list button disappeared now, new tab button still way to the right, empty space still there. https://i.imgur.com/Ho07q16.jpg Not Maximized, Customization active, moved tab list button to the left of the tabs, it doesn't use that empty space. https://i.imgur.com/HZ6Xfz9.jpg Maximized, Customization not active, empty space no longer there while maximized, new tab button still all the way to the right, tab list button shows and works while on the left of the tabs, this also happens while not maximized, I just forgot to take a pic. https://i.imgur.com/0u24OqL.jpg Maximized, Customization not active, moved tab list button back to the right next to the new tab button, doesn't show again. https://i.imgur.com/NU2317S.jpg If you need any more specific info just tell me :)