private void cmdAddSubMenu_Click(object sender, System.EventArgs e) { //Create a MenuDef object IMenuDef menuDef = new ToolbarSubMenu(); //Get the menu, which is the 6th item on the toolbar (indexing from 0) IToolbarItem toolbarItem = axToolbarControl1.GetItem(5); IToolbarMenu toolbarMenu = toolbarItem.Menu; //Add the sub-menu as the third item on the Navigation menu, making it start a new group toolbarMenu.AddSubMenu(menuDef, 2, true); cmdAddSubMenu.Enabled = false; }