Custom Form: [+Add] Field without Going to Grey Screen

[#1]

When working on Custom Forms view of Issues, Tasks, and Projects, there is a [+Add] button that allows users to edit the fields. I propose an improved user experience for editing these fields.

PROBLEM

It is mildly disorienting to be taken to a different view with a grey screen and seeing all the Custom Fields editable. The user has to re-orient themselves to the new view. Then the user has to scroll to the bottom of the list to click the Save button.

SUGGESTION

The user expectation should be to click [+Add] and just that field appear editable.

I propose:

1. When you click the [+Add] button, you just see the one field you're trying to edit.
2. When you click off of the field, it saves the data, rather than seeking out the [Save] button.