By default, the PopupAppearance property is NoBorder. The Background(exMenuFlatLineColor) property indicates the color of line that divides the left to right side of the menu, when the PopupFlatAppearance property is True. The PopupFlatBackColor property indicates the color to show the left part of the menu, when the PopupFlatAppearance property is True. The BackColor property specifies the menu's background color. The Background(exMenuSeparatorItem) property specifies the visual appearance of the separator items.