[Lazarus] win32 ShowScrollBar triggers immediate paint

[Mattias Gaertner]

On Sat, 05 Jan 2013 19:45:41 +0800
Paul Ishenin <webpirat at mail.ru> wrote:

> 05.01.13, 19:20, Mattias Gaertner пишет:
> > Hi,
> >
> > ShowScrollBar -> Windows.RedrawWindow
> >
> > Can some win32 developer explain, why the paint is immediate. Why not
> > queue?
> 
> Immediate is not extremely needed but why not to do so?

Because multiple changes to the scrollbar causes flickering.
The same with any change. That's why queued drawing should be the
default in all widgetsets.

> This is done to reduce the time when scrollbars are drawn wrong.

What is drawing wrong?

Mattias