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
private IDocument internalGetDocument(IFileEditorInput input) throws CoreException {
				IDocument document= getDocument(input);
				if (document != null)
					return document;
				return CompilationUnitDocumentProvider.this.createDocument(input);
			}
			
			public IBuffer createBuffer(IOpenable owner) {
				if (owner instanceof ICompilationUnit) {
					
					ICompilationUnit unit= (ICompilationUnit) owner;
					
					try {
						
						ICompilationUnit original= (ICompilationUnit) unit.getOriginalElement();
						IResource resource= original.getCorrespondingResource();
						if (resource instanceof IFile) {
							IFileEditorInput providerKey= new FileEditorInput((IFile) resource);
							
							IDocument document= null;
							IStatus status= null;
							
							try {
								document= internalGetDocument(providerKey);
							} catch (CoreException x) {
								status= x.getStatus();
								document= new Document();