Has any of the MAME/MESS developers any idea what could cause this problem, or which
source file could be the reason for it?
Problem fixed - I've found the solution by myself!
BTW, thanks for calling me a 'parasite'!
I've certainly spent much more than 1000 hours in the last years with improving the chess emulations
of MAME/MESS by adding support for chess pieces, and (different to a 'parasite') got NOTHING in return -
without these improvement the chess emulations would be in fact useless for any chess player.
And don't repeat again and again, that I'm obliged to publish my sources - I've released one of my source files
a few months ago on request of a MAME developer, and this was the result:
it has been included in the MAME sources (with lots of absolutely use- and senseless modifications), but has
been removed again already 2 or 3 days later - reason: "not the method we would want to use in MAME".
So why the hell should I publish my source code if it's not convenient at all for MAME (resp. for its developer)?
No need to answer this rhetorical question, because I'm now definitely leaving this 'friendly' forum ...