Hi there, I pushed some xinerama/updategeom() changes and some fullscreen handling changes into hg tip today.
The xinerama changes consist of a simplification when new screens are added/removed -- all clients are simply re-attached to the first screen found and the whole monitor structure is re-created freshly. This sucks in some cases, but introduces predictability, whereas the old code was rather unpredictive and cumbersome. Also, dwm now disallows resizing/moving/float fullscreen windows, as this doesn't seem very useful anyways. Please test hg tip and let me know any issues you encounter. Thanks, Anselm