User Text <Tab> cycling is broken


Step to reproduce (Rhino 6 SR30 2020-9-29):

  1. select an object
  2. go to ‘Attribute User Text’ property panel
  3. add a new key/value entry
  4. type the key field in
  5. hit <Tab>

Observed behavior:
The focus on the panel is lost and apparently goes nowhere.

How it should behave:
After hitting <Tab>, the focus/cursor should go to the value field.