Context 'Term parent' doesn't work

Using latest CTools dev.

1. Enable term_view page
2. Create a Variant.
2. Add `Term Parent` Relationship
3. Create a Taxonomy View (display type = content pane) with Argument input set to 'From context' = Term ID
4. Add the content pane to the page and configure it to take arg values from 'Term parent'

This doesn't work at all - the View gets its value from the Term, not from the Term Parent.

Workaround:

5. Change Argument input to pane config
6. Specify `%parent_term:tid` as argument value.
7. PROFIT!