I have a problem with fpga_editor as reported in bug 4062. With some help from #fvwm I managed to find something suspicious. fpga_editor does an UnmapWindow request and a MapWindow request right after each other.
An example program that does the same is located at http://www.da.isy.liu.se/~ehliar/priv/map_unmap.c . The example program will show a window for 1 second and it will then disappear if running under fvwm. The bug seems very similar to the bug reported in this thread: http://www.mail-archive.com/fvwm@hpc.uh.edu/msg08195.html /Andreas
