Increase height of Selection in search box
The ScrolledWindow has a default minimal height that shows at least two options. This does not give the hint to the user that more values are available. The height should depend on the number of options.
Since GTK3 switch, we have now access to new functions:
https://developer.gnome.org/gtk3/stable/GtkScrolledWindow.html#gtk-scrolled-window-set-min-content-height
https://developer.gnome.org/gtk3/stable/GtkScrolledWindow.html#gtk-scrolled-window-set-max-content-width
We could set a minimal height depending on the number of options and a fixed maximal height.