MouseUp event doesn't work on Groups

Working in Edge Animate 1.5, I have a symbol containing a group. I put a mouseup event on the group, but it doesn't fire when clicking the group (in the compiled animation I mean). However, if i put the mouseup event on one of the group's constituent elements, the event does fire when the object is clicked.

The group consists of a rounded rectangle and a text object to make a labelled button.

Is this a bug, or more likely, am I missing something? Or is there a better way to do this?

Any advice appreciated!

Cheers

Richard