How to cancel an event?

I have a macro which is triggered when I press RETURN inside of a text box :

if (code = 1280) then
blablabla
endif

However, I do not want a linebreak once I press return. How do I cancel the event? In javascript I would just use “event.preventDefault()”…

Did you read 14.3.6 of Anrew Pitonyak’s famous “Useful Macro Information”?

Thanks, I will take a look