OSX: zoom with 2 fingers triggers a menu in notebook

[efiring]

On OSX 10.14.5, Firefox, conda-forge, ipympl 0.3.3 widget in jupyter notebook:

After selecting zoom/pan mode with the toolbar button, the zoom works normally (one finger presses on the trackpad, the other drags), but panning with 2 fingers held down and dragging brings up a menu in addition to executing the zoom. The menu does not appear with %matplotlib notebook. Evidently it is disconnecting the 2-finger-press from the menu when the cursor is inside the figure.

[kboone]

I believe that this is the same issue as #143 which I fixed in #145.