Since 9.0.1 FP 10, and including V10 because it's largely identical for this purpose, I've encountered and seen others encountering a couple strange problems with compiling XPages projects. This is a perfect opporunity for me to spin a tale about the undergirding frameworks, but I'll start out with the immediate symptoms and their fixes.

So Domino 10 is upon us, marking the first time in a good while that Domino has had an honest-to-goodness version bump. More than anything, I think V10 is about that sort of mark. Its primary role in the world is to state "Domino isn't dead" - not exactly coming from a position of strength for the platform, but it's the critical message that HCL has to sell if they're going to be viewed as anything but coroners. Still, in addition to merely existing, V10 brings some changes that will help developers, particularly those - sadly - maintaining large legacy applications.