I experience more or less random lock-ups when using xfwm4 4.13.1. Especially with firefox, after 2-3 minutes of using it. The mouse cursor is still moving, but all the apps as well as xfce panels becomes unresponsive to input for roughly a minute. Also experienced this lock-up in hexchat. Reverting to 4.13.0 fixes this issue.
+1. In pkgsrc (the NetBSD package collection), we recently updated xfwm4 to 4.13.1 and see the same thing. As I wrote in http://gnats.netbsd.org/53718: "I see similar issues actually. As far as I can tell, xfwm4 wedges itself at some point when you move a window -- the first time works, then it somehow hangs. You may notice that in this situation, right-click on a title bar does not bring up a context menu. In this situation, you can still "pkill xfwm4", at which point xfce4-session will relaunch it and it will work again for a while."
I did a build with --enable-debug=full and get this log (assuming this is the part where I tried to drag a window and it did not move): TRACE[frame.c:133] frameBottom(): client "martin:/usr/pkgobj/wm/xfce4-wm/work/xfwm4-4.13.1/src " (0x1600002) TRACE[mypixmap.c:1049] xfwmPixmapFree(): pixmap 0x7f7fffffdd70 TRACE[mypixmap.c:1049] xfwmPixmapFree(): pixmap 0x7f7fffffde00 TRACE[mypixmap.c:1049] xfwmPixmapFree(): pixmap 0x7f7fffffde30 TRACE[mypixmap.c:1049] xfwmPixmapFree(): pixmap 0x7f7fffffdda0 TRACE[mypixmap.c:1049] xfwmPixmapFree(): pixmap 0x7f7fffffddd0 TRACE[events.c:2332] xfwm4_event_filter(): entering TRACE[events.c:2201] handleEvent(): entering TRACE[events.c:1313] handleConfigureNotify(): entering TRACE[compositor.c:3977] compositorHandleEvent(): event type 22 TRACE[compositor.c:3406] compositorHandleConfigureNotify(): window 0xe001eb TRACE[compositor.c:176] find_cwindow_in_display(): window 0xe001eb TRACE[compositor.c:156] find_cwindow_in_screen(): window 0xe001eb TRACE[events.c:2334] xfwm4_event_filter(): leaving TRACE[events.c:2332] xfwm4_event_filter(): entering TRACE[events.c:2201] handleEvent(): entering TRACE[events.c:293] handleMotionNotify(): entering TRACE[compositor.c:3977] compositorHandleEvent(): event type 6 TRACE[events.c:2334] xfwm4_event_filter(): leaving TRACE[event_filter.c:48] default_event_filter(): unhandled XFWM_EVENT_MOTION event TRACE[events.c:2332] xfwm4_event_filter(): entering TRACE[events.c:2201] handleEvent(): entering TRACE[events.c:293] handleMotionNotify(): entering TRACE[compositor.c:3977] compositorHandleEvent(): event type 6 TRACE[events.c:2334] xfwm4_event_filter(): leaving TRACE[event_filter.c:48] default_event_filter(): unhandled XFWM_EVENT_MOTION event TRACE[events.c:2332] xfwm4_event_filter(): entering TRACE[events.c:2201] handleEvent(): entering TRACE[events.c:293] handleMotionNotify(): entering TRACE[compositor.c:3977] compositorHandleEvent(): event type 6 TRACE[events.c:2334] xfwm4_event_filter(): leaving I can examine more details with gdb if someone points me at a good breakpoint setting. I can also make the full log available or do a new one.
Seems like this is fixed in 4.13.2