_winxptheme.EnableThemeDialogTexture
EnableThemeDialogTexture(hdlg, dwFlags)
Enables/disables dialog background theme. This method can be used to tailor dialog compatibility with child windows and controls that may or may not coordinate the rendering of their client area backgrounds with that of their parent dialog in a manner that supports seamless background texturing.
Parameters
ETDT_DISABLE to disable background texturing,
ETDT_ENABLETAB to enable the theme-defined background texturing using the Tab texture