[lazarus] Win32 bug: tcontrol's painting themselves in tgroupboxes

Micha Nelissen M.Nelissen at student.tue.nl
Sun Aug 31 14:59:38 EDT 2003

Mattias Gaertner wrote:

> On Sun, 31 Aug 2003 18:54:50 +0200
> Mattias Gaertner <nc-gaertnma at netcologne.de> wrote:
>>On Sun, 31 Aug 2003 16:58:18 +0200
>>Micha Nelissen <M.Nelissen at student.tue.nl> wrote:
>>>The problem is the following: if a tcontrol paints itself to it's parent
>>>DC, and the parent's clientrect is different than the origin, the 
>>>tcontrol's will paint themselves to the wrong position, namely the 
>>>parent.topleft, not the topleft of the clientrect. This happens with 
>>>TColorButton's in TGroupboxes for example. How do we solve this?
>>>FYI: Delphi has not solved this, a control at position (0,0) in a 
>>>tgroupbox is painted on top of the caption, while we want it in the 
>>An additional problem is, that the gtk paints before and the win32 paint
>>during message handling and they both uses different DC origins. There are
>>plenty of possibilities, where the origin can be moved to fix this. I will
>>also look into this ...
> Maybe I find a solution.

Hmm, not quite :(. The groupbox caption is not drawn anymore. It seems 
the window rect has stayed in the same position, but the whole box has 
moved up. Difference in top position of tcontrols and twincontrols has 
stayed the same.


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