Another thing: This problem actually appears even without FVWM's ManualPlacement, i.e. if the window is displayed immediately. So I suppose that it is likely to occur with other window managers.
A simple command to reproduce the issue: echo 'set terminal wxt; plot x' | gnuplot -persist -- Vincent Lefèvre <vinc...@vinc17.net> - Web: <https://www.vinc17.net/> 100% accessible validated (X)HTML - Blog: <https://www.vinc17.net/blog/> Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)
