Eclipse doesn't see classes from a plug-in dependency

I want to use Netty in an Eclipse RCP application. A开发者_开发技巧fter downloading the latest jar, I've added it to dependencies of my plug-in, but packages it provides aren't resolved in the editor. It's visible under "Plug-in dependencies" in the Package Explorer, as are all other dependencies (which work fine). How can I fix this?

What compilation error do you get when you import classes from netty? How did you create a plug-in project from the netty jar file? Did you use the "Plug-in from Existing JAR Archives" wizard? Are the packages of netty that you'd like to use exported in the manifest of the plug-in project of netty?