GTK+ Drop down menu to Toolbar Item

[chen donghai zte com cn]

Hi everyone:
    i need to drop down menu
from toolbar item. but don't know how to do it.
if use gtk_menu_tool_button_new, will
there is a down arrow to show menu on 
the right of toolbutton, need to show
menu by toolbutton not down arrow. please
refer to http://stackoverflow.com/questions/9132440/gtk-drop-down-menu-to-toolbar-item,
can you give me some suggestion or example?



Thank you very much.