Bug 93245 [Dialogs] Error messages show up in two locations in the properties dialog
Force an error message: 1) select a Java project 2) open the properties dialog 3) navigate to Java Compiler>Building 4) enable project specific settings 5) enter a letter into the maximum number of problems field ->the error message shows up at the bottom 6) resize the dialog ->the error message also shows up in the banner
bundles/org.eclipse.jface/src/org/eclipse/jface/preference/PreferenceDialog.java
/**
	 * The preference manager.
	 */
	private PreferenceManager preferenceManager;
	/**
	 * Flag for the presence of the error message.
	 */
	private boolean showingError = false;
	/**
	 * Preference store, initially <code>null</code> meaning none.
	 * 
	 * @see #setPreferenceStore
	 */
	private IPreferenceStore preferenceStore;
	private Composite titleArea;
	private Label titleImage;
	/**
	 * The tree viewer.
	 */
	private TreeViewer treeViewer;
	
    private ListenerList pageChangedListeners = new ListenerList(3);
	/**
	 * Creates a new preference dialog under the control of the given preference
	 * manager.
	 * 
	 * @param parentShell
	 *            the parent shell
	 * @param manager
	 *            the preference manager