At 100% zoom, the handles are easy to activate, even if the mouse is a
reasonable distance away from the handle. There is obviously some kind of "snap"
taking effect.

As the zoom is reduced, the handles are progressively more difficult to
activate. It can take several seconds of careful mouse positioning before the
mouse pointer changes to the dash with two arrow heads.

(At the same time, the actual size of the handles is reducing. I'm sure this is
non-standard.)

There is a "minimum zoom point". At zooms below this point, the handles cannot
be activated at all.

I'm sure that in other applications, the snap range and the handle sizes do not
decrease with decreasing zoom.