Recent versions of X (X.org server ≥1.11) support several debugging keysyms, introduced in this commit. When triggered, these perform actions related to grabs.
By default (at least in recent versions), these are disabled (absent from the default keymap).
However, if you have xdotool installed, it is possible to call them, by executing on the command-line:
xdotool key NameOfKey
where NameOfKey is the keysym you want to activate. For example, to print a list of active grabs to the X server log, use xdotool key XF86LogGrabInfo.
Relevant keysyms are:
- XF86LogGrabInfo: prints a list of active grabs to the X server logXF86LogGrabInfo: prints a list of active grabs to the X server log
- XF86Ungrab: breaks all active grabs, without killing the application that holds the grabs
- XF86ClearGrab: kills all processes that hold active grabs
Note that XF86LogGrabInfo only lists active grabs, not passive grabs such as a grab on a key which isn't currently pressed. If you want to get information about a passive grab, you need to activate the grab: run xdotool key XF86LogGrabInfo while the key chord or mouse button combination you're interested in is pressed. Do something like:
- Run
sleep 1; xdotool key XF86LogGrabInfo - Within 1 second, press the key chord or mouse button combination.
- After 1 second, release the key/button.
- Check the “Active grab …” information in the X server log (often
/var/log/Xorg.0.log).
