Bug report

The last example of the constrained layout guide (just merged) has a collapsed axes (bottom row):

https://matplotlib.org/devdocs/tutorials/intermediate/constrainedlayout_guide.html#sphx-glr-tutorials-intermediate-constrainedlayout-guide-py

This occurs because constraining different sized subplots is difficult, and constrained layout doesn't do it properly yet. I don't think this is a deal-breaker, its just an annoyance for people who want oddly-shaped subplot arrangements. I will try and work on getting it fixed (the complete collapse is already fixed, but it still doesn't get the ratio of sizes correct)...