[REGEDIT] the height of the XOR'ed splitter animation should be smaller and not cover the addressbar

We should reduce the height of the splitter XOR-line.

Benefit of that change is that this will elimnate the chance for drawing-dirt to remain within the addressbar.

See reproductionVideo
where I used our regedit on 2k3sp2.

The bug is in the Regedit binary.
reactos-bootcd-0.4.15-dev-8002-gbbb3b00-x86-gcc-lin-dbg.iso affected, mispaints already
reactos-bootcd-0.4.15-dev-6900-g7377f14-x86-gcc-lin-dbg.iso affected, mispaints already
reactos-bootcd-0.4.15-dev-1627-gaf0f858-x86-gcc-lin-dbg.iso affected, mispaints already
reactos-bootcd-0.4.15-dev-1-gd328584-x86-gcc-lin-dbg.iso iso affected, mispaints already
all heads of releases/0.4.7 to releases/0.4.14 are affected as well