By default, a co-author can't edit the idea he is assigned to. Here is a workaround to overcome this issue: make the co-author a state owner for a specific state. That will grant him with the editing permissions for that state.
To implement this, follow these steps:
1. As SysAdmin, Go to the main setting "Settings" option and then choose "Workflow".
2. For the state "Discussion" choose "Owner" icon from the list of icons:
3. Grant the Author/Co-author role the state owner permission:
4. Make sure you don't grant mistakenly state transition permission to the Author/Co-Author role:
After following these steps the co-author would be able to edit his idea.
You can verify the "State Owner" assignments by clicking the "Role Manager" menu option.
The result should be as follow:
