How can I determine the background color of a TTabSheet when running on a OS with themes like XP and above?
I would try GetThemeColor.
Edit: But note that tab sheets have a gradient under standard XP theming, so a single color probably is not what you need.
来源：https://stackoverflow.com/questions/2191301/how-can-i-get-the-color-for-a-themed-tabsheet