Comment 3 for bug 1864270

It's also not just that program, or possibly it not all the time

A re-launch of sgt-launcher and selecting "Bridges"

Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/sgtlauncher/SgtSocketLauncher.py", line 52, in callback
    withdrawn = self.wait_for_window_withdraw()
  File "/usr/lib/python3/dist-packages/sgtlauncher/SgtSocketLauncher.py", line 89, in wait_for_window_withdraw
    withdrawn = is_withdrawn(self.window_id)
  File "/usr/lib/python3/dist-packages/sgtlauncher/SgtSocketLauncher.py", line 178, in is_withdrawn
    withdrawn = not property_reply or property_value[0] == 0
TypeError: 'NoneType' object is not subscriptable

A re-launch of sgt-launcher and selecting "Flip"

Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/sgtlauncher/SgtSocketLauncher.py", line 52, in callback
    withdrawn = self.wait_for_window_withdraw()
  File "/usr/lib/python3/dist-packages/sgtlauncher/SgtSocketLauncher.py", line 89, in wait_for_window_withdraw
    withdrawn = is_withdrawn(self.window_id)
  File "/usr/lib/python3/dist-packages/sgtlauncher/SgtSocketLauncher.py", line 178, in is_withdrawn
    withdrawn = not property_reply or property_value[0] == 0
TypeError: 'NoneType' object is not subscriptable

I didn't explore much when first ran, I was summarizing Sean's blog for UWN & that made me want to look :)

I thought I had one open, but maybe I didn't (having opened it directly via terminal which does work for me; the launcher is where I'm having issues). I'll explore more if requested.