Hi everyone, I experienced the issue described above in both stable and testing.
Test case: $ xwininfo -root -tree | grep 0x | awk '{print $1}' | xargs -n 1 xwd -out tmp.xwd -id or get the id first, then dump $ xwininfo -root -tree | grep MyWindowName $ xwd -id MyWindowId Typical output from xwd: X Error of failed request: BadMatch (invalid parameter attributes) Major opcode of failed request: 73 (X_GetImage) Serial number of failed request: 15 Current serial number in output stream: 15 Note that when omitting -id and clicking the right window, the dump works fine. Stable: Linux 2.6.26-2-686 #1 SMP Wed Aug 19 06:06:52 UTC 2009 i686 GNU/Linux x11-apps 7.3+4 xserver-xorg 1:7.3+20 libx11-6 2:1.1.5-2 Testing: Linux 2.6.30-1-amd64 #1 SMP Sat Aug 15 18:09:19 UTC 2009 x86_64 GNU/Linux x11-apps 7.4+2 xserver-xorg 1:7.4+4 libx11-6 2:1.2.2-1 Regards, SB