WindowSetBackgroundStyle window style
Sets the background style of the window. The background style indicates whether background color should be determined by the system (wxBG_STYLE_SYSTEM), be set to a specific color (wxBG_STYLE_COLOUR), or should be left to the application to implement (wxBG_STYLE_CUSTOM).
On GTK+, use of wxBG_STYLE_CUSTOM allows the flicker-free drawing of a custom background, such as a tiled bitmap. Currently the style has no effect on other platforms.