SharePoint 2013 Task forms have a pretty nifty field called Related Items. It allows you to add a reference to another document or site asset to a Task. This is mainly used to display the related item that the task is created for (During a Workflow). Clicking on Add Related Item link and you get a dialog that allows you to
- Upload content from your desktop
- Select an item from a SharePoint list (yes you can link to a list item as well)
The problem is that this field is in the _hidden groups (must be a secret but i am not sure why it is hidden). To make it visible so you can use it in other lists you can do the following:
- Browse to the following URL to access the field edit form: [YourSiteURLGoesHere]/_layouts/15/start.aspx#/_layouts/15/fldedit.aspx?field=RelatedItems&Source=[YourSiteURLGoesHere]/_layouts/15/mngfield.aspx?Filter=All Groups
- Move the field to another (visible) group
I have tested this on both SharePoint on-premises and on-line and it works. Of course I don’t know if there is a reason why this is hidden so I am not sure if there are side-effects to doing this. One that I can think of is when it comes to migrations (especially using 3rd party Migration tools) this may not migrate as expected. You can of course set the field to “not hidden” in your SP 2016 environment before you migrate to SP 2016.