Fix keyboard focus issues

[Dmitry Timoshkov]

"Bernhard Rosenkraenzer" <bero at arklinux.org> wrote:

> The attached patch fixes bug #1798 (also known as 6986, 4042, 2819, 2149, and 
> 2926) -- some fullscreen applications not getting focus correctly.

As I already pointed out in the bug using window/screen width in comparisons
should allow to avoid that -1/+1 shift in left/top coordinate.

-- 
Dmitry.