Ok, that got rid of the compile errors. The IDE did some odd things with two exceptions ... RuntimeException and UnsupportedOperationException (these are probably the only java.lang exceptions in there). It failed to recognise them, then cycled a few times removing the import statement and putting it back again - after a couple of rebuilds that behaviour stopped, and I haven't been able to induce it again ... sorry that's a bit vague, but it was odd.
I'll have a look at the navigation issue again a little later