X hangs 100% cpu

[Die Optimisten <inform@die-optimisten.net>]

Hi

xserver-xorg-core    2:1.12.4-6+deb7u6
xserver-xorg    1:7.7+3~deb7u1
xserver-xorg-video-intel    2:2.19.0-6 (PC: Optiplex 755)

If making a screenshot with Firefox-Addon screengrab (often) Xorg hungs 
with 100% CPU
(Pressing Caps doesn't change the keyboard-leds, PC seems dead (display 
isn't updating, Xorg hangs)
But: killing (-3 before -9) Xorg and restarting Xorg solves the problem 
(until next time - that's no solution).

Sorry for attaching xorg-Log with backtrace (mailinglist-users don't 
like attachment, or has this changed meanwhile?)
but, I can't paste it here, and its too long)

Cause of fail: using xscreengrab-0.99.03c for firefox
I'm writing this to the Xorg-group, because no software should be able 
to hang Xorg!

* Could you add date-timestamps to the output of xorg-log ?
 (or: how do I convert  [ 84786.820] ( to low for seconds till 1970 !)

thank you
Andrew
PS: PLEASE also add me to every CC:, I#m not in this mailinglist!

Attachment: Xorg.log.gz
Description: GNU Zip compressed data