For what I want to do I need to have exclusive access to the keyboard events so that I can rewrite them. I have been experimenting a bit with this in XMonad, but passive grabs don't work. The problem with passive grabs is with overlapping events. This is what happens: * press key A * grab converts from passive to active * KeyEvent keyPress A is delivered to XMonad * B is pressed * KeyEvent keyPress B gets delivered to XMonad (B is registered as passive grab as well, but gets delivered, because technically, we're in an active grab now) * A is released * KeyEvent keyRelease A gets delivered to XMonad * active grab on A reverts to passive (incl some FocusEvents & KeymapNotify to inform us that B is still held) * B is released * KeyEvent keyRelease B gets NOT delivered to XMonad, it's a regular KeyEvent, no grab is active, and the passive grab on B is not triggered, because its keyPress event occurred during another (shadowing) activeGrab. (Actually, if you keep pressing B, after about a second or so, X realizes that there should be a grab active and enters the grab. Unfortunately, this is not fast enough when typing. Just to be clear, this is a problem of passive grabs, not with XMonad. Because of this behaviour it seems that the only thing that gets me there within X is a permanent active grab (keyboardGrab). Other extensions use active grabs, but they only do this for a limited time, usually after being triggered (eg. CycleRecentWS, Submap, GridHS, CycleWindows). So my questions: * Is such a permanent active grab a good idea within X? I'm worrying about problems interacting with other programs who might attempt grabs or XMonad losing the grab and not knowing about it. * If this is not a good idea, what should I look into to get this capability (exclusive access to transform the keyboard event stream, before it reaches any application). * Where/who should I ask to get an informed answer if not here? My end target are X applications, and I expect that there will be a tight integration with the window manager (likely XMonad). But I'm willing to look at a variety of points to hook into the event stream. Thanks