Vaadin plugin for eclipse

I’m going to write project using Your framework. During installation plugin to Eclipse (Vaadin plugin for Eclipse) I receive statement “Security Warning”. Despite, I was ignoring error, I can’t download all libraries, project is not properly compile. A few days ago when I make test and install plugin all work properly. The only way to create project is to use mvn (Maven).
Below I send screen with warning.
Bartłomiej Hawrot

The security warning is “normal” - many/most Eclipse plug-in authors do not sign their plug-ins. Obtaining a suitable code signing certificate is somewhat costly and might not be an option for some organizations, and signing implies some additional complexity in how builds are made. Vaadin plug-ins are signed but IvyDE (on which Vaadin plug-ins depend) is not.

Not being able to find any Vaadin classes is something I have seen from time to time. It is normal for the project to be in this state for a moment while IvyDE fetches dependencies, but sometimes IvyDE does not fetch them correctly and does not retry either. Manually triggering IvyDE->Resolve or IvyDE->Refresh from the project context menu might help in these cases.