Change Background of Menu

[vcstarter]

I try to change the background color of a menu, but the program crashed when the menu item is a separator. I try to check to see if there is a separator before I make the change, but I cannot get the checking type to work

 foreach (ToolStripMenuItem item in items)
            {
                if (!item is ToolStripSeparator)
                {
                    item.BackColor = color;
                    if (item.DropDownItems.Count > 0)
                    {
                        SetItemsBackColor(color, item.DropDownItems);
                    }
                }
            } 

any hint on getting this to work