gistfile1.cs

  	private void SelectAllClickHandler(object sender, EventArgs agrs)
		{
			designer1.ExecuteAction(DesignerAction.SelectAll);
		}


		private void DesignerForm_Load(object sender, EventArgs e)
		{

			
			var menuStrip = designer1.CreateToolStrips(DesignerToolStrips.Menu)[0];

			var editMenu = (menuStrip as MenuStrip).Items[1] as ToolStripMenuItem;
			var selectAllMenu = new ToolStripMenuItem("Select All", null, SelectAllClickHandler);
			editMenu.DropDownItems.Add(selectAllMenu);
  	}