property ComboBox.HeaderBackColor as Color
Specifies the header's background color.

TypeDescription
Color A  color expression that indicates the background color of the control's header bar. The last 7 bits in the high significant byte of the color to indicates the identifier of the skin being used. Use the Add method to add new skins to the control. If you need to remove the skin appearance from a part of the control you need to reset the last 7 bits in the high significant byte of the color being applied to the background's part.

Use the HeaderBackColor and HeaderForeColor properties to defines the colors for the control's header bar. Use the Def(exHeaderBackColor) property to change the background color or the visual appearance for a particular column, in the header area. If the Def(exHeaderForeColor) property is not zero, it defines the foreground color to paint the column's caption in the header area. Use the LevelKey property to display the control's header bar using multiple levels. Use the HeaderVisible property to specify whether the control's header bar is visible or hidden. If the control displays the header bar using multiple levels the HeaderHeight property gets the height in pixels of a single level in the header bar. The control's header displays multiple levels if there are two or more neighbor columns with the same non empty level key. Use the BackColor property to specify the control's background color.