when dragging windows, audio playback and other X drawing activities are interrupted. To Reproduce: Play anything through an alsa channel, e.g. beep-media-player, xmms, mplayer, etc. Grab any window and drag, do not let go of the drag button on your mouse. Playback freezes until you drop the window. I think maybe the drag handler is itself not event based so all the other X events are not getting pulled from the event queue and processed until you drop the window
Do you have opaque move diabled?
Yes, opaque move is off
That's why. To be able to draw the window frames using XOR ops on screen, xfwm4 has to grab the display (any WM I know who implements this technique does the same, that's not xfwm4 specific), which means that other apps cannot access the screen. Blocking for other apps means some X11 operations call block until the display is ungrabbed. It seems the players you mention have a single thread, as a blocking X call prevents the playback. Ideally, the playback and display should be in different threads so that even if the display is grabbed, playback is not affected. But that's something that belongs to the music players, not the WM. So in a nutshell, no bug here. Either enable opaque move/resize in xfwm4 or bug the authors of the players so that their software use diufferent threads for playback and display.