[Lazarus] Form in tab on Windows=>Failed to create win32 control, error: 0

[Reinier Olislagers]

In Turbobird
https://github.com/motaz/turbobird

when connected to a database, going to views/right click, Display View
DDL gives an error message instead of the expected form in a tab.

Error message:
Failed to create win32 control, error: 0 : The operation completed
succesfully
It occurs
- in the development version (Laz trunk, as well as Laz 1.2.2) as well
as release version TurboBird for Win32 1.0.2
- on my Windows7 system, as well as a Windows 2000 system

It does NOT occur on Wine on Debian unstable.
No problems on Linux. Other forms that are created in a similar way work ok.

The form is being created in a tabsheet:
procedure TfmMain.lmDisplayViewClick(Sender: TObject);
...
    // Fill ViewView grid
    ATab:= TTabSheet.Create(self);
    ATab.Parent:= PageControl1;
    fmViewView:= TfmViewView.Create(nil);
    fmViewView.Parent:= ATab;

if I comment out the last line, the bug does not occur.

Is this code incorrect or is there a problem with tabsheets and this form?

Thanks,
Reinier