No, this doesn't mean you're putting in a new feature while flying to a gig somewhere. Add On The Fly is a feature where a user may add to a list of existing entries. Often when entering an invoice there may be a requirement to add a customer the cannot be found in a picklist of customers. In many older systems the user would have to cancel adding the invoice, launch a separate customer form, add the customer and the restart the invoice.
Add on the fly would have permitted access to said customer form from within the invoice itself. A system that doesn't allow this is one of my favorite pet peeves ;).
How is this a framework issue? This is the responsibility of the application. If the user/app. requires being able to add records on the fly, then the app. should let them. It's pretty easy to drop a button on any form to support something like this.
This is a feature offered in some frameworks. See Framework Feature Chart. So of course it's a framework issue. It's a fundamental component of usability, so support for this typically goes into framework user interface classes. -- Steven Black
A simple button on the simple picklist form would have to summon a separate data entry form. A picklist form would not normally have corresponding save/cancel buttons. Allowing this functionality within a picklist form means it would not be a simple picklist form. -- Mike Yearwood