If the short source capabilities shows a warning icon, surely the long
form dialog should show the same information.

Now the PDO list in the new Source Capabilities dialog actually gets
populated.  It looks great, too, as per the mockup.

Now it has the real PD Power and Information.  The list has separators
too.

It's not functional yet, but it opens when the Source Capabilities list
item is clicked on the Sink page.  It looks about right, so that's a
start!