Dim parent window when popover is open
@aday I think this is a feature missing in gtk. All other platforms have this: Qt, android, windows, (probably apple) have this.
When a popup menu is open the background of the application should be dimmed.
Required functions would look like:
gtk_popover_set_dim_parent(GtkPopover *popover, gboolean dim);
gtk_popover_get_dim_parent(GtkPopover *popover);