https://bugs.winehq.org/show_bug.cgi?id=42606
--- Comment #1 from Rafał Mużyło galtgendo@o2.pl --- Created attachment 60851 --> https://bugs.winehq.org/attachment.cgi?id=60851 patch fixing the problem
Well, it took a significant number of stabs in the dark and a relay log, but I've found both the reason (SystemParametersInfo:SPI_GETNONCLIENTMETRICS) for this problem and a simple, yet pretty solution.
Already sent the patch to the list, but just in case it gets stuck somewhere, attaching it here too.