Combo box does not scroll for long lists
If you build a combo box that contains many entries, such that their display would not fit in the screen, in gtk+ 3.92.1 then on popping up the list you can not move/scroll down to the lower entries.
This is unlike the behaviour in gtk+ 3.22.26.
To see this compile the attached code gtk_combo_box_no_scroll.c as:
gcc ./gtk_combo_box_no_scroll.c $(pkg-config --cflags --libs gtk+-3.0)
and run to get the expected behaviour, and then
gcc ./gtk_combo_box_no_scroll.c $(pkg-config --cflags --libs gtk+-4.0)
and run to see the bug.
[ In addition, if these later entries are selected through mouse-scrolling over the closed combo box, then a subsequent pop-up of the combo box will fail to show any list, and will instead display a darkened un-popped combo box. As Daniel Boles's points out below, this is from https://bugzilla.gnome.org/show_bug.cgi?id=794036 ]