Bug 40785 [plan item] Overview ruler improvements
- navigation from ruler to editor - hovering over header area shows number of errors/warning (header annotations in general)
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/CompilationUnitDocumentProvider.java
if (info instanceof CompilationUnitInfo) {
			CompilationUnitInfo cuInfo= (CompilationUnitInfo) info;
			
			if (JavaPlugin.USE_WORKING_COPY_OWNERS)  {
				
				try  {
					cuInfo.fCopy.discardWorkingCopy();
				} catch (JavaModelException x)  {
					handleCoreException(x, x.getMessage());
				}
			
			} else  {
				cuInfo.fCopy.destroy();
			}
			
			cuInfo.fModel.removeAnnotationModelListener(fGlobalAnnotationModelListener);
		}
		
		super.disposeElementInfo(element, info);
	}
	
	/*
	 * @see AbstractDocumentProvider#doSaveDocument(IProgressMonitor, Object, IDocument, boolean)
	 */
	protected void doSaveDocument(IProgressMonitor monitor, Object element, IDocument document, boolean overwrite) throws CoreException {
				
		ElementInfo elementInfo= getElementInfo(element);		
		if (elementInfo instanceof CompilationUnitInfo) {
			CompilationUnitInfo info= (CompilationUnitInfo) elementInfo;