Pascal, et al. -
To bring this problem to a close, I had configuration problems in the unrecognized "bundling" projects. Executing "Maven > Update Project..." for the entire suite fixed this. The Update Projects step added Java and Plugin natures to each of the bundling projects, a .classpath, and a few .settings/ files.
Once all the "bundling" projects had the correct natures and configuration files, they were properly recognized as satisfying the MANIFEST.MF implied dependencies in the real plugin projects. This means that the Eclipse PDE/IDE listed those bundling projects within the Plugin Dependencies classpath container, and compilation errors from the unknown symbols were eliminated.
Due to the heavy-handed changes made by the Configure > Convert to Maven Project process, I had removed some of the created configuration files. Most obnoxious was Maven's insistence to reset the project to Java 1.5 (please, just leave it alone!). I guess one or more of the added natures was actually required.
Thanks
- Lee