LBreakout 2.6.3 when leaving fullscreen via Winkey, the startmenu draws at wrong y position, it should automatically close itself

0.4.10-RC-29-gf6a9392 gcc dbg lin
LBreakout 2.6.3 from rapps
VBox 4.3.12, VBEMP, inbuilt Mesa

Reproduction steps
-set ros desktop to 800x600 32bpp
-Run the application (it will start windowed)
-switch to fullscreen (by selecting that option from menu "graphics/display"), it wants to draw 640x480
-then hit winkey

Symptom
The start-menu opens at wrong position in y
StartmenuWrongY.png
0.4.10-RC-29-gf6a9392__wrongY.log
The bug happens for every game that has ingame a different vertical resolution to the selected desktop resolution in ros.

Expected result
2k3sp2_automaticallyClosesTheStartmenu.webm
is "virtually not affected". It does open the startmenu just for a fraction of a second, but then automatically closes it.

The symptom is known since at least 0.4.5RC2 where I observed it the first time.
(I needed to create this ticket as a fork from CORE-12263 to keep both tickets more distinct)