I am using Xephyr as a nested X server. When I am in Xephyr window and pres the key combination Control_L+Shift_L, Xephyr grabs my input (mouse, keyboard). This grab can be released with Control_R+Shift_R, as in API documentation for awesome, a highly configurable X window manager.

The problem is, these key combinations do not work reliably. Sometimes I have to press repeatedly to have any effect. This is very frustrating.

Is there any way to script these key-combinations using some tool such as xdotool? Or any other tool? I would create a script which I could run once I am trapped inside Xephyr and cannot leave.

I have tried the following and that does not work (no effect):

xdotool key Control_L+Alt_L+Shift_L
  • I don't really understand if you have tried xdotool already. According to its manual, xdotool key Control_L+Alt_L+Shift_L is supposed to work. Mar 3, 2015 at 3:27
  • @Teresa e Junior - that command does not work. Mar 3, 2015 at 9:44
  • Are you sure you need to use Ctrl+Alt+Shift and not only Ctrl+Shift? What does Xephyr titlebar says? My version says ctrl+shift grabs mouse and keyboard. Where did you get Xephyr from? Mar 3, 2015 at 16:37
  • Yes, I think that three modifiers is a bit too much, to be honest. Mar 3, 2015 at 16:37
  • It can be. One more thing @MichaelBoies, sorry if this is a stupid question but do you press these keys together or do you release them one after another? Try pressing ctrl+shift at the same time, it really works reliably Mar 3, 2015 at 16:40

1 Answer 1


I face the same issue. The magic trick is in the order of the keys. You have to:

  1. press and hold Ctrl
  2. press and release Shift
  3. release Ctrl

If you release the Ctrl before Shift, or use any other order, you will face the issue. Pressing those keys together at the same time makes the order random.

BTW. It doesn't depend on the WM at all. It seems to be Xephyr related.

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