GtkSeparatorToolItem looks wrong when added to panel!?

Hello guys, I have been using gtk fro a while, more specifically gtkmm. I’m new to these forums and not quite sure if this is the correct category so please execuse any mistakes in advance.

So I know that tool palettes cant have widgets added to them directly, only tool item groups. I have a group with all the buttons i want and its added and everythings good. then I wanted to add a separator, and i did the regular way, here is a snippet of the code.

Gtk::SeparatorToolItem *seperator = Gtk::manage(new Gtk::SeparatorToolItem());
   seperator->show();
   tool_item_group->insert(*seperator);

but the problem here is that the separator ends up looking like this.

p

also it runs with the error.
Gtk-CRITICAL **: 03:20:29.865: gtk_widget_set_focus_on_click: assertion ‘GTK_IS_WIDGET (widget)’ failed