I have m2e 1.0.100 and wtp 3.3.1, they are the latest right?
I tried to revert to a version of my project that I knew was working and the problem remain the same, so it have to be something in eclipse.
I should try to delete the workspace and recreate it, but actually I'm working on a different project. Will try when I switch again to that project.
Thanks again,
Andrea