If you’re running the create row as a row action I believe that the row in context gets passed into the snippet. Try putting a

console.log(arguments);

in the beginning of your snippet and see what you get. I think it’g going to be something like this:

var params = argumentse0],<br>&nbsp; &nbsp; model = params.model,<br>&nbsp; &nbsp; item = params.item,<br>&nbsp; &nbsp; row = item.row;<br>console.log(row); // should be the row you want

While Moshe was thinking in code,  I was thinking declaratively.  But ran into a problem. 

If you are using the following method to pass the contactID into the Who ID,  you should be able to subsequently edit the value. 
- On your Task model add a condition on WhoId that is filterable default off. 
- Add a second condition on Who.Name that is filterable default off. 
- In your “Before Load Actions” on the drawer have a sequnece as follows:
      - Activate the WhoId  condition and give it the value of the contact_c from the row in context. 
      - Activate the Who.Name condition and give it the value of the contact__r.Name field from the row in context. 
      - Query the Task model (but Merges in new Rows into the existing set)

Now we run into a problem.  When you add a new task inside the drawer, and go to edit the WhoId - we throw a javascript error because the WhoId is a polymorphic field.  We are working to fix this bug,  but I think you can get around the issue if you force the WhoId always to refer to a Contact record.  Here is a post describing how to do that.  

Thanks to both of you!  

Rob, I did what you said and it works perfectly.  I already had a custom snippet running on the contact to define WhoId, so - no errors.

Sweet!!!

Thank you both!!!   Saved me a ton of time!