Thanks for playing. Yeah not sure where to move the 3d fold controls. It needs to not block wasd movement. Shift was already used for the parallel world preview. ctrl activates a lot of browser shortcuts if you press WASD with it(can happen easily while moving). For now I've added an additional binding for 3d folding to shift and the preview to c.
MMB scrolling on webGL is an oversight. I'll see what I can do fix it.
I don't understand what you mean by where you create the 3d fold not mattering. Maybe since your screen started scrolling on MMB, it only made vertical 3d folds which would look quite similar regardless of where you made the fold. Do you remember if the x marks after 3d folding were always horizontal?