Intermittent hanging on Add screen when attempting to change Note type

steps to reproduce:

  1. Open deck
  2. Click add
  3. Click Note type
    Add screen then hangs. When I close the app i get the following message:

Anki 2.1.37 (6d596c8f) Python 3.8.6 Qt 5.14.2 PyQt 5.14.2
Platform: Windows 10
Flags: frz=True ao=False sv=1
Add-ons, last update check: 2020-12-23 10:57:02

Caught exception:
Traceback (most recent call last):
File “aqt\”, line 87, in _on_closures_pending
File “aqt\”, line 59, in
File “aqt\”, line 76, in wrapped_done
File “aqt\”, line 114, in on_future_done
File “aqt\”, line 892, in on_collection_sync_finished
File “aqt\”, line 671, in reset
File “aqt\”, line 2650, in call
File “aqt\”, line 135, in onReset
File “aqt\”, line 112, in redraw
RuntimeError: wrapped C/C++ object of type QListWidget has been deleted


Running “Check Database” does not fix the problem.

I’ve added this to Avoid exec_() in · Issue #26 · ankitects/help-wanted · GitHub