In X11 there are several situations where the keyboard can be 'captured' by a process resulting in key events not propagating to the window manager. Some examples are:
- When a virtual machine has focus + keyboard capture
- When Xephyr has keyboard capture
- When the screen lock is active (not as important)
I'm interested in some kind of visual indication from my window manager for when a window is not only active, but is stealing focus from the WM as in some situations behavior is confusing.
Is this possible under X11? Sample code would be helpful so I can integrate it within my WM.