Quick create form automatically pull through look ups from original form

I'm currently trying to copy a quick create form from one system to the next and on the original form there is a function that I can't seem to replicate.

My payment entity has 3 lookup fields - Development, Development Unit and Sales Progression. If you are on the Sales Progression form and click on 'Add payment' on the payment sub grid, then the quick form will automatically pull through the sales progression (as expected) but then also pull in the development and development unit, which is populated on the sales progression form. My relationships between the entities are identical and there doesn't seem to be any javascript.

Any ideas? Please see an example below.