Bug 17566 Browsing Java src not on class path
When browsing Java src which is not on the classpath it is annoying to have millions of Quickfix light bulbs and error indicators. I suggest to disable this feature and have a special icon in the editor tab to indicate that the source file is not on the classpath and therefore behaves differently in certain operations (search, quickfix, etc.)
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/CompilationUnitDocumentProvider.java
fOverlaids.add(annotation);
			}
			/*
			 * @see IProblemAnnotation#removeOverlaid(IProblemAnnotation)
			 */
			public void removeOverlaid(IProblemAnnotation annotation) {
				if (fOverlaids != null) {
					fOverlaids.remove(annotation);
					if (fOverlaids.size() == 0)
						fOverlaids= null;
				}
			}
			
			/*
			 * @see IProblemAnnotation#getOverlaidIterator()
			 */
			public Iterator getOverlaidIterator() {
				if (fOverlaids != null)
					return fOverlaids.iterator();
				return null;
			}
		};
		
		/**
		 * Internal structure for mapping positions to some value. 
		 * The reason for this specific structure is that positions can
		 * change over time. Thus a lookup is based on value and not
		 * on hash value.
		 */
		protected static class ReverseMap {