What version of Skuid are you running? From the Task object I was able to select all the items in who.

9.5.3

Which contact fields are you not allowed to add?

I’m only able to add those listed on the screenshot.  I want to be able to add all the other contact fields (both standard and custom).

Have you seen this post?
https://community.skuid.com/t/contact-model-based-on-event-whoid-for-account-view?topic-r…

The WhoID and WhatID seem to operate a little bit differently than normal objects. I think it’s because WhoID and WhatID can be a number of different objects, and we won’t know until runtime which object you’ve chosen for them. As a result, it can’t let you pull in fields that are specific to only one object.

It’s pulling in the correct Contact ID.  How can I otherwise link so that it shows the contact object?