I'm using XFce-4.8 with Gentoo GNU/Linux (current kernel is 3.0.6-gentoo). On my old slow x86 workstation (Pentium(R) 4 CPU 3.00GHz with only 512 Mb RAM) rather often (seems to be a result of intense disk work) I see the following issue: DE "looses" keyboard input. Menu/window list windows also fails to display. xsession (currently slim.log) contains the following error message: /var/log/slim.log: ... ** (xfdesktop:2831): CRITICAL **: Unable to get keyboard/mouse grab. Unable to pop up menu ... Switching to console (Ctrl-Alt-F1) with login and sending HUP signal to process returns normal operation. /var/log/slim.log: ... xfdesktop[4258]: starting up ... I'm using now xfce-extra/xfce4-xkb-plugin-0.5.4.3. Earlier (excuse me, I don't remember version) I've experineced similiar issue seemed to be provided with xfce4-xkb-plugin, now (with listed version) it works fine. On my another workstation (much more new system amd64 arch on Intel i5 CPU and with 8Gb RAM) the issue is much more rare, but seems also to appear (I'll make a check in about this week-end).
Can you check out bug 441 and bug 7172 and see if they are related to your problem? https://bugzilla.xfce.org/show_bug.cgi?id=7172 https://bugzilla.xfce.org/show_bug.cgi?id=441 This may help you speed up locating exactly where your problem is.
(In reply to comment #1) > Can you check out bug 441 and bug 7172 and see if they are related to your > problem? > https://bugzilla.xfce.org/show_bug.cgi?id=7172 > https://bugzilla.xfce.org/show_bug.cgi?id=441 > > This may help you speed up locating exactly where your problem is. First of all I am to say, that check available logs on my amd64 workstation don't showed this issue (so, it _may_ me x86-specifig, or provided by memory handling). Bug 441 exactly the same. The only difference is in that I invoke menu not by keyboard short-cut, but by desktop right-button click (the same issue with window list, invoked by center-button mouse click). Bug 7172 --- sometimes I see and this issue. But it looks not to correspond with reported one.
Just today I've got another issue looking related. Ot the same workstation (x86 arch, only 512Mb RAM, heavy loaded) mouse pointer becomes cross (I don't guess how/why) and don't exited this state. Desktop actions (including unheading panel) together with keyboard input becomes blocked. But unlike previous case, no errors in xsession log presents.
Fixed in master. The fixes are available in the 4.11 dev releases and will be apart of the next 4.12 stable release. Marking resolved.