Have app that starts 3 thread and waits to terminate then

Question

Have app that starts 3 thread and waits to terminate then

repeat this

when i set the freeonterminate to true app will stuck in thread.waitfor . why ?

for TIndex := 0 to 3 do
begin
SetLength(TThread, Length(TThread) + 1);
TThread[Length(TThread) - 1] := TThread.Create;
Sleep(1000);
end;

for TIndex := Low(TThread) to High(TThread) do
begin
TThread[TIndex].WaitFor;
end;