[Lazarus] When do we use clForm, clWindow, clBtnFace?

[Marc Weustink]

Graeme Geldenhuys wrote:
> Hi,
> 
> Relating to the bug report that mentions that clForm should rather be
> the default color for a TCustomForm instead of clBtnFace.
> 
> http://bugs.freepascal.org/view.php?id=13577
> 
> I fully agree with the bug report - clForm backs a lot more sense that
> clBtnFace. But that made be think a bit more...
> 
> 
> When do we use clForm, clWindow, clBackground and clBtnFace.
> 
> What is the difference between clForm and clWindow?  Isn't a TForm
> also a Window?  Then again, couldn't clForm and clWindow be removed
> and we simply use clBackground? If not, where am I supposed to use
> clBackground then?

clWindow is the backgroundcolor of a edit control. When using 
clBackground, it is clear for "default" controls, but what if I want a 
panel with the color of the background of an edit (or a form) ?

> These pre-defined colors are quite confusing when you think about it.

For the default cases they might be, in tose cases using clDefault would 
be better, but if you want to color something you need to know the color.

Marc