If a user does something like

fig,axs=plt.subplots(2,2,layout='constrained')..plt.tight_layout()

tight_layout is called, andconstrained_layout is ignored. This was originally done becauseconstrained_layout was experimental. However, people seem to thinkconstrained_layout is not working because they have copy-and-pasted, or reflexively addedplt.tight_layout.

I'd propose that we at least warn ifplt.tight_layout is called on a figure with an active layout manager. I'd also be open to this being an error.