I see now, the DrawingStyle property have influence.
You're right. DrawingStyle gdsThemed has the dark skin problem.
Isn't it just a matter of keeping the original DrawingStyle when grid must be skinned and setting it to gdsClassic. Then restoring its original if skinning is switched off?
I also noticed that in dark skins the row and column lines are too pronounced. I'll make a new topic of that.