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/CompilationUnitDocumentProvider.java
}
			}
			private void  overlayMarkers(Position position, ProblemAnnotation problemAnnotation) {
				Object value= getAnnotations(position);
				if (value instanceof List) {
					List list= (List) value;
					for (Iterator e = list.iterator(); e.hasNext();)
						setOverlay(e.next(), problemAnnotation);
				} else {
					setOverlay(value, problemAnnotation);
				}
			}
			/**
			 * Tells this annotation model to collect temporary problems from now on.
			 */
			private void startCollectingProblems() {
				fGeneratedAnnotations= new ArrayList();
			}
			/**
			 * Tells this annotation model to no longer collect temporary problems.
			 */
			private void stopCollectingProblems() {
				if (fGeneratedAnnotations != null)
					removeAnnotations(fGeneratedAnnotations, true, true);
				fGeneratedAnnotations= null;
			}
			/*
			 * @see IProblemRequestor#isActive()
			 */
			public boolean isActive() {