DelphiVCL for Python threading - python-3.x

Question

Using DelphiVCL for Python it seems to be blocking threads.
Testing the code (below) I would expect it to output / update timing from the two - 2 - threads. However the VCL app seems to be blocking the other threads.
How can this be fixed to allow running background threads with VCL?
from delphivcl import *
import threading
from time import sleep, strftime as now
from datetime import datetime
FORMAT = '%Y-%m-%d %H:%M:%S'
class Thread(threading.Thread):
def __init__(self, parent, threadname):
super(Thread, self).__init__()
self._stop = threading.Event()
self.parent = parent
self.name = threadname
def run(self):
while not self._stop.is_set():
text = "{0} {1} {2}".format(now(FORMAT), self.name, str(self._stop.is_set()))
if self.parent:
self.parent.lblHello.Caption = text
else:
print(text, flush=True)
sleep(1)
print(now(FORMAT), self.name, str(self._stop.is_set()))
def stop(self):
self._stop.set()
class GUIApp(Form):
def __init__(self, owner):
self.OnDestroy = self.__form_ondestroy
self.lblHello = Label(self)
self.lblHello.SetProps(Parent=self)
self.thread = Thread(self, 'inside app')
self.thread.start()
self.lblTimer = Label(self)
self.lblTimer.SetProps(Parent=self)
self.lblTimer.Top = 16
self.timer = Timer(self)
self.timer.Interval = 1
self.timer.OnTimer = self.__form_timer
self.timer.Enabled = True
def __form_timer(self, sender):
self.lblTimer.Caption = datetime.utcnow().strftime(FORMAT + '.%f')[:-3]
def __form_ondestroy(self, sender):
self.thread.stop()
if __name__ == '__main__':
Application.Initialize()
Application.Title = "Hello Delphi VCL"
app = GUIApp(Application)
app.Show()
t2 = Thread(None, 'outside app')
t2.start()
FreeConsole()
Application.Run()
app.Destroy()
t2.stop()
EDIT: Adding a timer (code updated) to the VCL app starts the background threads.