I removed the code in webAgg_core that prevented a user from being able to differentiate between middle click and right click events with amouse_button_event callback. I removed this forcing of the reported button from 2->3. This code was originally added to account for difficulties in preventing the context menu in chrome 23#1426 (comment) which in modern chrome should be possible. There was a comment asking to remove mention of this from the MouseEvent docstring, however the current docstring does not seem to mention this so I did not change anything there.

Closes:matplotlib/ipympl#254
Closes:#18171

PR Summary

PR Checklist

• Has Pytest style unit tests (does remove code require writing a new test?)
• Code isFlake 8 compliant
• na New features are documented, with examples if plot related
• na Documentation is sphinx and numpydoc compliant
• na Added an entry to doc/users/next_whats_new/ if major new feature (follow instructions in README.rst there)
• na? Documented in doc/api/next_api_changes/* if API changed in a backward-incompatible way