Bug 96917 [implementation] If two editors use the 2.x-compatible API, one or both doesn't work
At least one problem is that 3.0 installs partitioners for every editor that might possibly edit a file, but each editor expects its own partitioner to be installed. Leading to the famous white screen with blue line.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/ClassFileDocumentProvider.java
* Creates a new document provider.
	 */
	public ClassFileDocumentProvider() {
		super();
	}
	/*
	 * @see StorageDocumentProvider#setDocumentContent(IDocument, IEditorInput)
	 */
	protected boolean setDocumentContent(IDocument document, IEditorInput editorInput, String encoding) throws CoreException {
		if (editorInput instanceof IClassFileEditorInput) {
			IClassFile classFile= ((IClassFileEditorInput) editorInput).getClassFile();
			document.set(classFile.getSource());
			return true;
		}
		return super.setDocumentContent(document, editorInput, encoding);
	}
	/**
	 * Creates an annotation model derived from the given class file editor input.
	 * 
	 * @param classFileEditorInput the editor input from which to query the annotations
	 * @return the created annotation model
	 * @exception CoreException if the editor input could not be accessed
	 */
	protected IAnnotationModel createClassFileAnnotationModel(IClassFileEditorInput classFileEditorInput) throws CoreException {
		IResource resource= null;
		IClassFile classFile= classFileEditorInput.getClassFile();
		IResourceLocator locator= (IResourceLocator) classFile.getAdapter(IResourceLocator.class);
		if (locator != null)
			resource= locator.getContainingResource(classFile);
		if (resource != null) {