Hi Dan,
Sorry it has taken so long to get back to this.
You have been busy indeed. The issue raised appears fixed.
There are a couple of new issues however. I will mention them here and set up a new ticket.
1. Kanban preferences|Columns. Using fixed columns. You select the custom attribute fine, but the Attribute values in the grid are only ever the Attribute values of the first custom attribute.
2. If using 'the following fixed columns only', the 'Attribute to track' selections disappear. This means to turn it off again, you need to go through Preferences again. Suggestion: Have an entry in the 'Attribute to Track' list like 'Custom Attribute - fixed', to allow easier switching between views. Or another entry into options 'Show Fixed columns'.
3. If using 'the following fixed columns only', the Preference 'Always show backlog column' is not honored.