The option, you are referring to, is only available for Merge Areas mapped to a Checkbox- or Multiple Choice field.
Unfortunately, it is not possible to activate this option for other merge areas as well. Currently, we don't have any information about the future planning.
We would like to invite you to provide your feedback on our customer feedback forum: http://docuware.uservoice.com/
There you can share new ideas and feedback regarding all DocuWare modules and get in contact with our product team. Our partners and customers can vote for these ideas and thus specify whether the functions are useful.
The higher a feature is voted, the better are chances that it will be implemented in future versions.
With best regards,
Specialist Software Support Team ORANGE EMEA