do you want to grab keyboard input?
grab mouse input?
confine the mouse cursor to inside this window?
Note: it is extremely rude to do this without good reason. Reasons may include doing some kind of mouse drag operation or popping up a temporary menu that should get events and will be dismissed at ease by the user clicking away.
Prior to March 11, 2021, grabbing the keyboard would always also set the X input focus. Now, it only focuses if it is a non-transient window and otherwise manages the input direction internally.
This means spurious focus/blur events will no longer be sent and the application will not steal focus from other applications (which the window manager may have rejected anyway).
Grabs exclusive input from the user until you release it with releaseInputGrab.