As a regular Form addon user, it has always frustrated me that I have to use the standard Person or Family selectors to add a new person \ family to the form. I often have the required person\family already visible in the Person\Family\Relationship view.
So, to improve this, I’ve added drag and drop support 
There are a couple of screen shots in the pull request which show me dragging a person, from the person view, and dropping onto the form. This is a census for, so it adds a new row. If you drag and drop a second person, it will simply add another new row to the form.