Check In Project takes into account external changes

This is a change from Ariadna, I believe.
This should be made an option (Especially due to the dismal performance of the diff dual tree view of the Check In Project http://www.intellij.net/forums/thread.jsp?forum=13&thread=28442&tstart=0&trange=100 )

How can a plugin have a say in what really goes in the checkin before the tree is displayed?
At the time of the refresh that detect external changes would a VirtualFileListener be called and can I make the file up-to-date at that point?

Another question: the new FileStatusProvider is nice but when is it called? It seems like it is called a lot.

Jacques