With our nightly builds for Spring IDE M3 we had to update the spring.jar within the plugin "org.springframework" a few times to adopt the changes Juergen made to enhance Spring's tooling API.

Therefore users of the previous nightly builds should (at least) delete the plugin "org.springframework" from their local Eclipse installation and and reinstall it from the Spring IDE updatesite or the archived updatesite. Otherwise they might run into issues like the one from ticket #506.