Checksum plugin "auto recalculate" for verify cmd

[Eric]

Would be nice if the checksum plugin (verify) supports "auto recalculate".

More exactly: adding something like a FileSystemWatcher as in .NET, when a underlying file change, the checksum is recalculated.
Now I need to close the plugin and redo the verify.

If this is too much work, adding a button or F5 for "Recalculate"?

Thanks