[Lazarus] PageControl color

[Benito van der Zander]

>
>
> TTrackBar is a windows common control. We need to correct win32 
> widgetset code to let it draw transparently on parent controls if themes 
> are enabled. Feel free to create a patch which solves this problem.
>   
I tried to create one, but now there is another problem:
The TrackBar sets WindowInfo.ThemedCustomDraw := true in its 
CreateHandle. If you remove
this, it is draw right, when the window is shown the first time.
But as soon as the parent is redraw (for example when it is moved beyond 
the screen borders and back)
the trackbar gets invisible.
Any suggestions what to do against this?

> And, btw, color is not clWhite - theme services are using bitmaps to 
> draw control surfaces. If you change theme to another it can look as 
> Blue or Black or as any other color.
Is there a way to retrieve the correct color, when the surface is filled 
with a single color?

Benito