A single function or pair of functions similar to $fieldname $entname which indicate the field the cursor currently occupies/would occupy if the struct editor were in force.
Recent tests appear to point out that $fieldname and $entname do not indicate the current position of the cursor. Which I can understand for the use of some of the triggers. I need, however, to be able to tell which field the cursor was in for the instance during the form loses focus trigger (amongst others) to allow for a context sensitive control on another instance. This is not available, and the code therefore has to have extra code in the field gets focus trigger of all painted fields, storing the information in a component variable, forcing all fields to be detached from the model.