[Lazarus] Thread finalization

[Leonardo M. Ramé]

I'm having a rough time with Threads.

When my app starts, it creates an instance of a TThread that loads a
bunch of images. That TThread instance can be destroyed in two ways:

1) When the loading finishes.
2) When the user closes the app while loading.

In case 2, I destroy the thread using this code:

  if Assigned(FMyThread) then
  begin
    FMyThread.Terminate;
    while not FMyThread.Finished do
      CheckSynchronize(100);
    FreeAndNil(FMyThread);
  end;

This works ok.

Now, in case 1, I thought that I should assign an OnTerminate event to
the thread, then destroy it, but it doesn't work as expected. The app
gets locked on my thread destroy event:

  procedure TForm1.Createthread;
  begin
    FMyThread := TMyThread.Create;
    FMyThread.OnTerminate := @ThreadDestroyEvent;
    FMyThread.Start;
  end;

  procedure TForm1.ThreadDestroyEvent(Sender: TObject);
  begin
    FMyThread.Free;
  end;

  destructor TMyThread.destroy;
  begin
    // destroy internal objects
    inherited destroy; // <-- The app gets locked here!!
  end;

Why is this happening?, am I doing something wrong?.

-- 
Leonardo M. Ramé
http://leonardorame.blogspot.com