Event.CANCEL is not implemented

I am using the FileReference component to upload files from my system. But I can't catch when user cancels popup because CANCEL event doesn't exist in event class. There is this event in Flex.

Start by locating the FileReference component and its Event class, then compare the available events with the Flex behavior referenced in the issue. Done means a user cancelling the file-selection popup produces a catchable CANCEL event; add or update the relevant event coverage if the repository provides it.

Written by the indexing model from the issue text.