In release note of 7.3.0, this ticket was marked fixed. https://docs.sencha.com/extjs/7.3.1/guides/whats_new/release_notes.html
But I do not see the code change as per suggested here: https://forum.sencha.com/forum/showthread.php?469880-Cannot-read-property-viewModel-of-null
May I know is this actually fixed?
This is 7.3.0.55 as I downloaded: