Bug report

Bug summary

All's in the title.
Note that #17772 is necessary to avoid throwing an exception due to a logic error, but even with it, the rubberband is invisible.

Expected outcome

Matplotlib version

• Operating system: archlinux
• Matplotlib version: master
• Matplotlib backend (print(matplotlib.get_backend())): gtk3agg/gtk3cairo
• Python version: 38
• Jupyter version (if applicable):
• Other libraries: pygobject 3.36.1, may be worth trying earlier ones... (if it's a regression there this may not be release critical)