I've noticed an annoyance recently. In FF38, there appears to be an area 1px in height above the tabs bar that appears to be what's left of the titlebar. Clicking on this space doesn't select the tab just below it, but the entire FF window, which you can then drag around. I submit that this behavior is not very useful and leads to slower browsing because I always must be sure the cursor is just below that 1px line. Otherwise you end up unmaximizing and dragging around windows. Doing some research I've found that this topic has been previously broached here: https://support.mozilla.org/en-US/questions/1013963 The one suggestion was to add the following line to userChrome.css (and before everyone asks, yes, I do have this set up properly and have seen it work by setting weird numbers and colors for UI elements): [code] #TabsToolbar {margin-top:-1px !important;} [/code] This didn't work for me. I found another questioner who asked that this 1px line be restored: https://support.mozilla.org/en-US/questions/942800 But adding this line (substituting 1px for -1px also didn't solve my problem: [code] #main-window[sizemode="maximized"] > #titlebar { margin-bottom: -1px; } [/code] This behavior occurs even with all UI extensions (e.g. Classic Theme Restorer) disabled, so it's not one of those causing this phenomenon. The UI extensions I do have also offer no fix for this problem. At this point, I'm out of ideas. Can anybody help?