Introduced by #2056.
@mdboom, it works fine for me on gtkagg, but not on gtk3agg. Evidently I didn't test the latter fully. I am looking into it now. Does it fail for you on gtkagg also, with Fedora?
I had earlier tried putting in an explicit call to "destroy()", and that solved the original problem, at least on gtkagg; but then I thought that was overkill if simply removing the "hide()" would have the same effect. I still don't see any logic to using "hide".
For me, it fails on both GtkAgg and Gtk3Agg, but is resolved in both cases by your fix in #2073. Thanks for getting to the bottom of this!