I missed the implications of #3552 when it went through.

If any part of the plot image is transparent, a full image frame is sent in order to make sure there isn't any ghosting. The default value of nbagg.transparent == True unfortunately means that full images are always sent for every frame. This results in lower framerates and flickering.

I can workaround this by setting figure.facecolor: white and nbagg.transparent: False, but I wonder if we shouldn't make this the default. 2.0 might be a good opportunity to make figure.facecolor: white the default for every backend anyway, which does generally look more modern.

It does mean it IPython ever changes their style to something on a non-white background things may not look as nice, but we'll cross that when we get there.

Cc: @pelson