Similar to the functionality of the Timeline, it would be beneficial to have more control over the actions that can be performed from a subgrid. We don't always want to allow access for users to create a new record from a subgrid, and in the instances where they could/should create an item from the subgrid, it would be a better experience if we could allow them to create directly from the subgrid (like a quick create form), rather than navigating away from the record.