BGE play stops when moving window (Please, need to know if this is normal)

making a network multi player Tux Kart game wannabe.

On windows 8.1, using Regular Python from intalled from *.exe (instead of bundled python (v.3.3))
included bgui , Pyro4 (networking)
Blender 2.69.0 r60995

All is fine, going from bgui layout to start game server (subprocess), to layout waiting for all connected players to connect and start game, to first game scene (playable)… BUT

if I move the window - the game ends ! It’s like using the escape key… no output message, no hanging, no other problems, I can just restart and all is fine.

Now I’m in dev mode, so not such a problem but I can imagine a player moving a window out of the way and stopping is BGE (oups!)

Mostly done in Python - no code pertaining to stop engine.

Is this behavior 1- normal, 2-expected ???

thanks in advance

Further test show it as the same behavior even if using blender’s Python dll (play quits)