Reworked FileActions to use Desktop.open. It will be accessible not only on Windows, but on all systems where java.awt.Desktop and java.awt.Desktop.Action.OPEN is supported.
Actually, there is not much sense in "Open containing folder" action. There should be another action: "Show in folder", which brings up Explorer and selects the item there.
There is a question as to how to do it. Actually all that java.awt.Desktop does is to simply call ShellExecute, which doesn't seem to do the trick in any way.