In evaluating the most recent matplotlib code, @TD22057, myself, and others on our team have come across several issues. Some are bugs and some are performance issues that make interactive usability difficult. I am opening this issue to list them all at once. This way when I submit my pull requests with the fixes, I can just reference this issue. I am also listing them all here to give you a heads up to the issues we found and that there are fixes coming.

The issues are as follows:

• BarHCollection is very slow
• stale artists do not handle being removed from axes properly
• position of text annotations looses unit information
• polar plots do not properly handle units polar plots do not properly handle units #4905
• broken_barh does not properly support units
• figure option dialog does not properly handle units
• generating fontconfig strings from mpl FontProperties is broken generating fontconfig strings from mpl FontProperties is broken #4910
• Super short lines with arrows do not act well
• qt imports do not pick defaults properly
• animation blitting is no longer working
• mouse movement is very slow
• Agg restore_region is broken
• qt backend default bbox not set when blitting
• qt backend draw_idle doesn't work
• qt backend has more draws than necessary
• text update properties does not handle bbox properly
• bar plot fails with no tick labels

I already have fixes for almost all of these and will be submitting them in the next day or so (with more details about each one).

Edited to add a missing issue I forgot the first time.