I did not comment on #7066 because I did not get an email alert when the ticket was modified.
But the situation is much worse than described above. The window starts out maximized, but it is possible to
user window manger short cut keys to move and resize.
But that is only the beginning of the problems :-) Attempting to (say) open a file, the new window appears
but any mouse (well touchpad) clicks hide the window under the main window. The next click raises it again,
but it is not actually possible to enter data. This continues indefinitely.
If only the keyboard is used, it is possible with ingenuity to enter a valid file. The file appears to load (gpx)
but the main window shows a blank area.
So josm latest is completely broken under xfce4 and current debian testing. I have just been testing with version 4643.
ATM I can't maintain my areas of OSM :-(
ael