public static ToolStripDropDown add_DropDown_Button(this ToolStripDropDown dropDown, string text, Image image, Action onClick) { return(dropDown.invokeOnThread( () => { var newButton = new ToolStripButton(text); newButton.Click += (sender, e) => O2Thread.mtaThread(() => onClick()); newButton.Image = image; dropDown.Items.Add(newButton); return dropDown; })); }