The type org.eclipse.core.runtime.IConfigurationElement cannot be resolved

When building my Eclipse RCP Application, I get the following error.

The type org.eclipse.core.runtime.IConfigurationElement cannot be resolved. It is indirectly referenced from required .class files.

I have included the org.eclipse.core.runtime library in m开发者_C百科y dependencies, so I am not sure what the problem is.

As mentioned in this thread

Don't include the jar files manually [in the plugin.xml file). Use the dependencies tab in your plugin.xml editor to manage the dependencies on the plugins.

Here is the graphical illustration of what that means:

alt text http://img91.imageshack.us/img91/923/eclipsercpruntime.png

Double-click on the MANIFEST.MF file, and through the 'Dependencies' tab, just add org.eclipse.core.runtime, and it will add other dependencies, including org.eclipse.equinox.registry, which includes your missing class!