Question

Is this the most efficient way to listen to mouse events on the background of a group?

<s:Group width="200" height="100" rollOver="group1_rollOverHandler(event)" rollOut="group1_rollOutHandler(event)">
    <s:Rect width="100%" height="100%">
        <s:fill>
            <s:SolidColor alpha="0"/>
        </s:fill>
    </s:Rect>
</s:Group>

seems pretty minimal, but alpha = 0 is not the most efficient thing out there.

Answer 1

I’m listening for mouseDown and mouseUp on a Group with nothing in it (for dragging) and it’s working just fine. A quick test with rollOver and rollOut reveals those events to be fired as expected.

I’d do this as it avoids having a fill with alpha=0:

<s:Group
  width="{width}"
  height="20"
  rollOver="_onRollOver(event)"
  rollOut="_onRollOut(event)"/>

EDIT: Realized I forgot to directly address the question. Narf!
To the best of my knowledge this is the most efficient way to listen for mouse events on a Group since we are not drawing anything at all, ever by using an empty Group.