this is a kind of weird bug, so I hope there'l be enough info to help debug.
Ok, this is the situation. I'm using VMware workstation on my Xfce Desktop (4.4.2). It seems that, as soon as I try to enter fullscreen in vmware (using ctrl+alt+enter), X modifiers are gone. (see xmodmap before and after, attached).
I have a win+d shortcut, wich is bound to "show desktop".
After that, only typing D shows the desktop. Not all shortcuts are affected like theses. For example, running commands doesn't work anymore, but the key affected doesn't run the command without modifier, for example.
Another example is that Ctrl+Fx (bound to "go to desktop x") doesn't work at all, but using Fx doesn't work either. The "d" thing is quite strange. (it's the only xfwm shortcut using super). Alt+tab works correctly, for example.
If I try to kill xfwm, and rerun it, using "d" makes it segfault. I attach a backtrace, but with an optimized build, so I guess it won't be really helpful. I'll try to build a non optimized one and report back.
Created attachment 1547
backtrace from xfwm4
Created attachment 1548
xmodmap output after the bug
Created attachment 1549
xmodmap output before the bug
As a side note, it doesn't happen in vmplayer using the "maximize" button in Xfwm4 (wich pass vmplayer window on fullscreen), and it doesn't happen either when using the menu item "Full screen" in VMware.
So I guess there's some kind of a race condition in vmware or xfwm4 wich leads to that. Ctrl+Alt is also the shortcut used to leave the vm focus.
I just tried using a different shortcut (Ctrl+Shift) and it seems to work.
So I guess, it may be a problem in vmware wich is badly handled by xfwm. When trying Ctrl+Alt+Enter, "Enter" may be understood as "enter the vm" while "Ctrl+Alt" is understood as "leave the vm". And during this, the fullscreen event occurs.
I guess it'll be not really easy to debug vmware…
The backtrace is not really usable, all I can tell is that we reach a an abort in gdk, not much.