I use Debian OS, and I use DWM window manager.
I am unable to click the menu dropdowns (or any dropdown) unless the window is perfectly in the center of the screen. If it’s elsewhere, all dropdowns, when clicked, immediately close.
After some experimentation, it seems that when the GanttProject window is not centered on my monitor, the mouse does not align with the application. But this only effects drop down menu clicks. All other functions still work.
Another issue is that full screen doesn’t work:
