I've modified the OTB Translation Review workflow to remove the Reject activity:
After my translation job comes back from TMS and the workflow enters the Translation Review activity I've opened the site in XPM and started the review activity form the Things to do area.
When I click Finish - the Accept activity is automatically selected - expected:
But, the problem is when I click Done, I get and error that the next Workflow activity has not been selected?
This doesn't happen when I finish the activity via Workflow Administration. The dialog uses a drop-down for the next activity, I can select Accept and finish:
This feels like a bug in XPM.