Dragging the preview area left and right in Glyphs 3 stops working a lot. I drag it around a few times and it freezes in place. To fix this I toggle “Always center active glyph” on or off, sometimes twice, and it starts working again.
“Always center active glyph” sometimes works even when it is not checked.
I am currently using build 3099. I have had these problems since Glyphs 3 was released.