Sets whether to show an overflow menu when @toolbar isn’t allocated enough
size to show all of its items. If %TRUE, items which can’t fit in @toolbar,
and which have a proxy menu item set by gtk_tool_item_set_proxy_menu_item()
or #GtkToolItem::create-menu-proxy, will be available in an overflow menu,
which can be opened by an added arrow button. If %FALSE, @toolbar will
request enough size to fit all of its child items without any overflow.
Sets whether to show an overflow menu when @toolbar isn’t allocated enough size to show all of its items. If %TRUE, items which can’t fit in @toolbar, and which have a proxy menu item set by gtk_tool_item_set_proxy_menu_item() or #GtkToolItem::create-menu-proxy, will be available in an overflow menu, which can be opened by an added arrow button. If %FALSE, @toolbar will request enough size to fit all of its child items without any overflow.