Bug 81083 [preferences] Mark Occurences enablement not adhered to
I200412142000 - open preference page with Mark Occurences preferences - enable Mark Occurences - Apply - Restore Defaults - OK -> toolbar shows Mark Occurences as 'enabled', editor marks occurences -> on preference page the preference is disabled
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/ToggleMarkOccurrencesAction.java
JavaPluginImages.setToolImageDescriptors(this, "mark_occurrences.gif"); 
		setToolTipText(JavaEditorMessages.getString("ToggleMarkOccurrencesAction.tooltip")); 
		WorkbenchHelp.setHelp(this, IJavaHelpContextIds.TOGGLE_MARK_OCCURRENCES_ACTION);		
		update();
	}
	
	/*
	 * @see IAction#actionPerformed
	 */
	public void run() {
		fStore.setValue(PreferenceConstants.EDITOR_MARK_OCCURRENCES, isChecked());
	}
	
	/*
	 * @see TextEditorAction#update
	 */
	public void update() {
		ITextEditor editor= getTextEditor();
		
		boolean checked= false;
		if (editor instanceof JavaEditor)
			checked= ((JavaEditor)editor).isMarkingOccurrences();
			
		setChecked(checked);
		setEnabled(editor != null);
	}
	
	/*
	 * @see TextEditorAction#setEditor(ITextEditor)
	 */