Open requested to merge scrollable_parents_have_precedence into main
Scrolling a GtkScrolledWindow should have precedence over child widgets that also react to scrolling like GtkComboBox, GtkScale and GtkSpinButton, because otherwise when you're in the middle of scrolling the window you can involuntarily scroll over the widgets and change its values. This problem can be seen in applications like pavucontrol, gnome-control-center audio page, gnome-tweaks, devhelp prefs, and so on. However this patch allows to scroll the child widgets when the GtkScrolledWindow itself cannot be scrolled (i.e. when no scrollbars are shown because window height exceeds the content).
Fixes issue #3092