[Lazarus] savedialog is not shown

[Andrea Mauri]

Il 11/07/2012 11:21, Mattias Gaertner ha scritto:
> Can you test if a savedialog can be shown before calling the
> function?
> Maybe it has nothing to do with this function.

Yes, the savedialog is always shown.

In order to be clearer, the software is this
http://talete.mi.it/products/dragon_description.htm
it is a software that calculates molecular descriptors

after calculation descriptors can be saved, the savedialogs (like all 
the other dialogs) is always shown when I want to save the descriptors 
after calculation

recently I noticed that if I load a particular set of molecules, after 
the calculation I am not able to show any dialog, everything in the 
software works fine but no dialogs are shown (only on windows, on linux 
it works fine)

I am not able to understand why since no particular exceptions are 
raised, the only thing is that when I call the execute method the 
dialogs are not shown returing mrCancel

as reported in a previous mail I noticed

I look deeper and I found that in:

class procedure TWin32WSOpenDialog.VistaDialogShowModal(ADialog: 
IFileDialog; const AOpenDialog: TOpenDialog);
var
   FileDialogEvents: IFileDialogEvents;
   Cookie: DWord;
   CanClose: Boolean;
begin
   FileDialogEvents := TFileDialogEvents.Create(AOpenDialog);
   ADialog.Advise(FileDialogEvents, @Cookie);
   try
     AOpenDialog.DoShow;
     repeat
       ADialog.Show(GetParentWnd);

--> I set a breakpoint on the line below, the dialog is not shown, 
UserChoice in the following 'if' line is  mrNone, so different from mrOk 
and then UserChoice is set to mrCancel

       if (AOpenDialog.UserChoice <> mrOk) then
       begin
         CanClose := True;
         AOpenDialog.DoCanClose(CanClose);
         AOpenDialog.UserChoice := mrCancel;
       end
       else
         CanClose := True;
     until CanClose;
   finally
     ADialog.unadvise(Cookie);
     FileDialogEvents := nil;
   end;
end;