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
* Uninstalls the synchronizer.
		 */
		public void uninstall() {
			JavaCore.removeElementChangedListener(this);
		}
		/*
		 * @see IElementChangedListener#elementChanged
		 */
		public void elementChanged(ElementChangedEvent e) {
			check(fPackageFragmentRoot, e.getDelta());
		}
		/**
		 * Recursively check whether the class file has been deleted.
		 * Returns true if delta processing can be stopped.
		 */
		protected boolean check(IPackageFragmentRoot input, IJavaElementDelta delta) {
			IJavaElement element= delta.getElement();
			if ((delta.getKind() & IJavaElementDelta.REMOVED) != 0 || (delta.getFlags() & IJavaElementDelta.F_CLOSED) != 0) {
				
				if (element.equals(input.getJavaProject()) || element.equals(input)) {
					handleDeleted(fInput);
					return true;
				}
			}
			if (((delta.getFlags() & IJavaElementDelta.F_ARCHIVE_CONTENT_CHANGED) != 0) && input.equals(element)) {
				handleDeleted(fInput);
				return true;
			}
			if (((delta.getFlags() & IJavaElementDelta.F_REMOVED_FROM_CLASSPATH) != 0) && input.equals(element)) {
				handleDeleted(fInput);