Opened up thunderbird today and found it spread across the two screens of my setup. SUSE Linux Tumbleweed latest build on a laptop with second monitor above the laptop screen. Double click does not return the window to a single screen, there is no maximize button, and trying to drag the height fails. It's locked to a height over more than a single screen. Creating a new profile fixes the problem, and I could try dragging 50Gb of historic material and configuration of filters over to the new profile, but there is obviously something in the settings that by deleting it, the current profile will work properly again? Main problem is when I move away from home I don't have the top monitor and can't access emails on the bottom of the screen. All other windows simply revert to the laptop screen ...