Hi!
As I mainly try winboard for variants, I found some strange behaviour while selecting xiangqi or shogi (must be true for other non standard sizes I guess):
I open winboard in edit mode with a rather smal size (middling for exemple as it as the pieces needed for the cited variants), but every time I move the window (by clicking then dragging the window upper bar) the size gets bigger (and then, I lose the embeded pieces). For xiangqi, it grows up until I moved the window enough times to reach the "huge" size, while for shogi, it grows up 3 times then stabilizes (but also with the "huge limit if I started with a big enough size).
Another minor problem occurs if I use textures for the squares : when I switch from normal chess to the variant, there are some squares ok and some with flat colors. The textures become all ok after a resize (while moving the window for example :P).