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
reg.put(PREF_DLG_TITLE_IMG, ImageDescriptor.createFromFile(PreferenceDialog.class,
				"images/pref_dialog_title.gif")); 
	}
	/**
	 * The current preference page, or <code>null</code> if there is none.
	 */
	private IPreferencePage currentPage;
	private DialogMessageArea messageArea;
	/**
	 * Indicates whether help is available; <code>false</code> by default.'
	 * 
	 * @see #setHelpAvailable
	 */
	private boolean isHelpAvailable = false;
	private Point lastShellSize;
	private IPreferenceNode lastSuccessfulNode;
	/**
	 * The minimum page size; 400 by 400 by default.
	 * 
	 * @see #setMinimumPageSize(Point)
	 */
	private Point minimumPageSize = new Point(400, 400);
	/**
	 * The OK button.
	 */
	private Button okButton;
	/**
	 * The Composite in which a page is shown.
	 */
	private Composite pageContainer;