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
*/
			protected void fireModelChanged() {
				fireModelChanged(new CompilationUnitAnnotationModelEvent(this, getResource(), true));
			}
			
			/*
			 * @see IProblemRequestor#isActive()
			 */
			public boolean isActive() {
				return fIsActive && (fCollectedProblems != null);
			}
			
			/*
			 * @see IProblemRequestorExtension#setProgressMonitor(IProgressMonitor)
			 */
			public void setProgressMonitor(IProgressMonitor monitor) {
				fProgressMonitor= monitor;
			}
			
			/*
			 * @see IProblemRequestorExtension#setIsActive(boolean)
			 */
			public void setIsActive(boolean isActive) {
				if (fIsActive != isActive) {
					fIsActive= isActive;
					if (fIsActive)
						startCollectingProblems();
					else
						stopCollectingProblems();
				}