When using Linux Mint Fluxbox 9 there's a bug with preserving windows size after changing display resolution from higher one to lower one. If you open an app and your display resolution is 1600x1200, than you close it, restart the system and change the monitor and its resolution to 1280x720. Then you open the same application, its window keeps having the same size as in 1600x1200 resolution. The result of it is, that it doesn't fit the desktop and you're completely unable to control that window. There should be some auto resize window function implemented.