@QuLogic, I just tested the macosx cursors a bit. It didn't have anything to do with this PR. Master is the same behavior as 3.4.2.

Somehow it has to do with the plotted mappable on the axes...

import matplotlib.pyplot as plt

fig, ax = plt.subplots()

ax.contourf([[0, 1], [2, 3]])  # cursor changes to the grab/zoom image
# ax.imshow([[0, 1], [2, 3]])  # cursor does not change

plt.show()

It works properly for contourf, but not for imshow/pcolormesh. The cursor works as expected for all mappables with qt5agg.

Originally posted by @greglucas in #20620 (comment)