Feature request #247: REQUEST: Help button and feedback icon when entering license code

From a user email:

'Details: the first time I tried to paste the serial number "nothing happened", so I re-copied and then pasted the number in. What had actually happened on the first attempt was that I had in fact pasted the serial number PLUS a carriage return. My second attempt had no leading or trailing spaces, but was preceded by an entire line that couldn't be seen.

feature suggesion: do not allow multiple lines of text in the serial number entry field. More generally, raise a helpful error to the user if the serial number or mail entry contains obviously invalid characters.'

My reply:

This is a good idea. I do strip whitespace (spaces, tabs, newlines) internally, but there is no visual indication if you accidentally post two whole lines in. I think a little warning icon that appears when too much (or too little) text is entered would be good, along with a small help button that you can click on to find out what might be wrong (or a tool-tip).

I am currently using a standard NSTextField to receive the text but I could subclass it or add an NSFormatter to add some custom behaviour.