I created validators for required fields. My transition from To Do to In Progress is simple, with only 3 validators:
- If a value for fields Assignee, Due date, Original estimate, Start date is not provided during the transition, show the following error: This field is required.
- Verifies that field Due date is greater than or equal to now. Only date part.
- Verifies that field Start date is greater than or equal to now. Only date part.
They are working fine when doing the transition using a drop down in the Edit Issue screen and when a filed value is missing, an error message is returned. However when doing the same transition from Board view by dragging and dropping the issue on next status in the workflow, all validators are ignored.
I don't have any transiton screen configured, because I don't need it and I am using a business project template.


