[Lazarus] Paintbox complete redraw

[Benito van der Zander]

>
> If you replace
>     rgb(random(255),random(255),random(255))
> with
>     rgb(100, 100, 100)
> you'll not notice the repainting because it will be painted in the same indistinguishable colour as before
Yes, of course, but I need to draw something like a mini screenshot 
which is different nearly every time it is drawn and depends on the 
position of
every window.

So how can you redraw the paintbox complete in OnPaint?

Benito