AS3 Warning: 1090: Migration issue: The onRelease event handler is not triggered automatically by Flash Player at run time in ActionScript 3.0.  You must first register this handler for the event using addEventListener ( ‘click’, callback_handler).

AS3 Warning 1090 Description:

So the other day I opened some AS2 files that I use for teaching Flash Arrays at UVU.  I changed a few things in the file and tested my movie.  That is when Warning 1090 popped up and I realized that I had missed a few things.  AS3 Warning1090 is the most comprehensive and complete error message that I have ever encountered in Flash or Flex.  Not only does it give a really clear description but it tells you how to solve the issue.  Kudos Flash programmers/writers.  Jen DeHaan  if this is you – Nice Job!

P.S.  This will also happen with onEnterFrame, onPress, onMouseMove, etc…  I have only included one example here but it applies to all cases.

Flex / Flash Error #1090 Fix:

Do exactly what the message says use an event listener instead of the onRelease event that was common in AS2.

Bad Code:

joinArray_btn.onRelease = function () {
//Do Something
}

Good Code:

joinArray_btn.addEventListener(MouseEvent.CLICK, joinArray);

function joinArray() {
//Do Something
}

Related Errors:

AS3 Warning 1058

This should help you resolve Flex / Flash Warning #1090

Thanks and as always Happy Flashing

Curtis J. Morley