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
} else {
					document= createEmptyDocument();
				}
					
			} catch (CoreException x) {
				document= createEmptyDocument();
				status= x.getStatus();
			}
			
			fireElementContentAboutToBeReplaced(element);
			
			removeUnchangedElementListeners(element, info);
			info.fDocument.set(document.get());
			info.fCanBeSaved= false;
			info.fStatus= status;
			addUnchangedElementListeners(element, info);
			
			fireElementContentReplaced(element);
			fireElementDirtyStateChanged(element, false);
			
		} else {
			super.resetDocument(element);
		}
	}
	
	/**
	 * Returns the preference whether handling temporary problems is enabled.
	 */
	protected boolean isHandlingTemporaryProblems() {
		IPreferenceStore store= JavaPlugin.getDefault().getPreferenceStore();