public static void setMergeAction(ToolStripMenuItem MainFile) { MainFile.MergeAction = MergeAction.MatchOnly; MainFile.MergeIndex = 3; ToolStripMenuItem menu; // var eintrag1 = contextMenuStrip1.Items.Cast().Where(m => m.Text == "Eintrag 1").FirstOrDefault(); ToolStripItemCollection coll = MainFile.DropDownItems; // ToolStripSeparator foreach (ToolStripItem control in coll) { if (control.GetType().Name.Equals("ToolStripMenuItem")) { menu = (ToolStripMenuItem)control; menu.MergeAction = MergeAction.MatchOnly; menu.MergeIndex = 3; setMergeAction(menu); } } }