I won't answer the question directly, I'll leave that for the developers to comment.
However rather than misusing a buttonedit to add an image and identify special fields, did you consider using Presentation Styles either backgroundColor or backgroundImage?
Secondly your screenshot indicates you have address fields and you are presumably looking to make sure the address is entered correctly. You could still use a TextEdit and add some logic to concatenate your 4 address fields into 1 string for the textedit, and split the resulting string back into your 4 address fields on the way out. The question can also be asked, do you still need 4 address fields, they tend to be a hangover from character screens.
Finally if you are checking addresses, there are web services around that do address validation. Even the Google Geocoding API can be used. You had an Irish address so I'll illustrate with our Irish address, if I spell address correctly, the geocode API returns a result
https://maps.googleapis.com/maps/api/geocode/json?address=Smithstown+Industrial+Estate,Shannon,Irelandif I do a misspelling e.g. Smithtown instead of Smithstown,
https://maps.googleapis.com/maps/api/geocode/json?address=Smithtown+Industrial+Estate,Shannon,Ireland Google is clever enough to make an intelligent guess and suggest the correct address, the formatted_address and partial_match fields can be used to identify if this has occurred.
Hope that helps
Reuben