I had a look at Royale’s mx FileReference emulation to remember the
implementation. Doesn’t look like there’s an option for multi select. I think
it would require adding a bead that extends
org.apache.royale.file.beads.FileBrowser and adds the multiple attribute to the
delegate which is an
Possibly because we started out targeting IE8.
I'd also check on how those values compare in different scrolling
implementations in Flash. There was a mask property in old MX components, and
scrollRect in Spark components. And then I think virtual scrolling might have
worked slightly
