Input Event Handling

Glynn Clements glynn at
Thu Apr 5 05:34:51 PDT 2007

Thorsten Wilms wrote:

> > Input focus is to a particular window, so you get device -> kernel -> X
> > server -> app.
> There are cases like sliders in a windows with scrollbars. With 
> gtk+ at least, if the pointer is on the slider, mouse-wheel will 
> move the slider. But with the pointer anywhere else, the wheel 
> scrolls.
> Does this mean that input focus has to be redone on the window/ 
> application level for things like this to work?

The mouse wheel generates button events, not key events; there are
some differences in the way that the two are handled. In particular,
unless there is a grab active, button events are always reported to
the window under the pointer; there is no persistent "mouse focus" in
the same sense that there is a keyboard focus.

Glynn Clements <glynn at>

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