A
focus policy. The
window manager gives the
keybooard focus to the
window the
mouse pointer is in.
This is almost never the default, but nonetheless probably the most common focus policy used on X; it's also available on Windows if you install TweakUI, but doesn't work well.
Annoyances:
- If you (or someone else) jog the mouse accidentally, keystrokes may be lost or even go to some other window.
- May still need to click to focus on a particular text field of the window.
- When pointing at the background, nothing gets keystrokes (except maybe the window manager).
- Interacts poorly with dialog boxes and keyboard-driven focus changes.
- The mouse pointer must remain in the window, obscuring a portion of it (although some applications, e.g. (X)Emacs with mouse-avoidance-mode, will warp the pointer when it gets in the way of typing).