Hi Ronald,
I found this earlier on this forum.
GtkRcStyle* rc_style;
rc_style = gtk_rc_style_new();
rc_style->bg[GTK_STATE_NORMAL].red = 0;
rc_style->bg[GTK_STATE_NORMAL].green = 0;
rc_style->bg[GTK_STATE_NORMAL].blue = 0;
rc_style->color_flags[GTK_STATE_NORMAL] = GTK_RC_BG;
gtk_widget_modify_style(widget,rc_style);
gtk_rc_style_unref(rc_style);
I put this in a function called SetBackgroundColor
-Mark