[lazarus] listbox patch

[Vincent Snijders]

> -----Oorspronkelijk bericht-----
> Van: Micha Nelissen [mailto:micha at neli.hopto.org] 
> Verzonden: maandag 15 december 2003 23:00
> Vincent Snijders wrote:
> 
> > Attached patch enables storing objects in a listbox or 
> checklistbox. 
> > The problems I predicted with the implementation came true. In some 
> > applications the destructor of the list called first and after that 
> > the LCL destroys the handle, sometimes it is the other way 
> around. I 
> > think I have captured both cases in the patch.
> 
> Good work there, the patch looks good. 
Well, I have to look into this again, because the patch is not good
enough. Lazarus still leaks a bit of memory when the debugger options
dialog is used. (Tested both windows 98 and windows 2000). Further
research to find out why, is needed. I will do before the end of the
week.
> I added a check for nil result.
I thought a nil result wouldn't happen, but I forgot to test adding just
strings (without objects) to the listbox.

Vincent.