"pass-through" GtkOverlay child property doesn't work when the child has its own children
Steps to reproduce
Compile the attached overlay.c (gcc $(pkg-config --cflags --libs gtk+-3.0) overlay.c). Comment out gtk_fixed_put(drawings, drawing, 0, 0);. See that clicking the button works and prints to stdout. Put the line back. See that it no longer reacts to clicks.
Current behavior
Expected outcome
The property being respected regardless of the parental status of the child.
Version information
3.24.26 on Gentoo GNU/Linux.