Bug 131771 Match animated message behaviour in Preferences
An enhancement should be made to Preferences so that warnings and errors show up in a sliding message area like it they do in TitleAreaDialog.
bundles/org.eclipse.jface/src/org/eclipse/jface/preference/PreferenceMessageArea.java
public PreferenceMessageArea(PreferenceDialog preferenceDialog) {
		this.preferenceDialog = preferenceDialog;
	}
	/* (non-Javadoc)
	 * @see org.eclipse.jface.dialogs.DialogMessageArea#createContents(org.eclipse.swt.widgets.Composite)
	 */
	public void createContents(Composite parent) {
	       
        
        titleLabel = new CLabel(parent, SWT.NONE);
        titleLabel.setFont(JFaceResources.getBannerFont());
        
        messageArea = new MessageArea(preferenceDialog.formTitleComposite, SWT.NONE);
        messageArea.setFont(JFaceResources.getDialogFont());
   		messageArea.setVisible(false);
	}
	/* (non-Javadoc)
	 * @see org.eclipse.jface.dialogs.DialogMessageArea#setMessageLayoutData(java.lang.Object)
	 */
	public void setMessageLayoutData(Object layoutData) {
		((FormData) layoutData).top = null;
		((FormData) layoutData).right = new FormAttachment(100,-getTitleLabelOffset());
	     messageArea.setLayoutData(layoutData);
	}
	/**
	 * Calculates the width difference between the title label and the parent composite
	 * of the message area. Required for when the workbench adds a toolbar to the
	 * preference dialog.
	 * 
	 * @return the width difference if the calculation yields a value > 0, otherwise it