Diablo II leaves the taskbar visible while being in main menu

0.4.12-RC-39-g27da885 gcc dbg lin is affected.
VBox 4.3.12, VBEMP, ros internal mesa, desktop resolution 800x600, 32bpp

When you start "Diablo II demo" from rapps in fullscreen, which is the default,
it will leave the taskbar visible.
(Later ingame after switching the resolution another time, the taskbar will vanish).

I know that this issue happens at least since every ros release >= 0.4.2.