It’s almost impossible to use the drag handles to adjust margin and padding now. Any small adjustment of 1-15px doesn’t register as smoothly as it used to. Only when dragging the handle fast do you get a response. Try to use the padding drag handles to alt-click and drag a 15px padding. Good luck.
This new style panel should have been tested for much longer before removing the legacy style panel. I think with all these bugs we should at least have access to the legacy style panel while you work this out.