Bug 146159 [Regression]Changing font operation doesn't work other than the first time
Description: The first time changing operation can work well. However, Change it again, it won't work. Steps: 1.Insert lable/text to layout or master page 2.Change the font from serif to cursive, it works well 3.Change the font again Result: The action doesn't work Additional infor: build number:200606080632
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/ui/dialogs/HighlightRuleBuilder.java
private PreviewLabel previewLabel;
	private DesignElementHandle designHandle;
	private boolean isBoldChanged, isItalicChanged, isUnderlineChanged,
			isLinethroughChanged;
	private static final String DEFAULT_CHOICE = Messages.getString( "HighlightRuleBuilderDialog.text.Default" ); 
	private static final String[] SYSTEM_FONT_LIST = DEUtil.getSystemFontNames( );
	private static final String VALUE_OF_THIS_DATA_ITEM = Messages.getString( "HighlightRuleBuilderDialog.choice.ValueOfThisDataItem" ); 
	/**
	 * Default constructor.
	 * 
	 * @param parentShell
	 *            Parent Shell
	 * @param title
	 *            Windows Title
	 */
	public HighlightRuleBuilder( Shell parentShell, String title,
			HighlightHandleProvider provider )
	{
		super( parentShell, title );
		this.provider = provider;
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.jface.dialogs.Dialog#createContents(org.eclipse.swt.widgets.Composite)
	 */
	protected Control createContents( Composite parent )
	{
		GridData gdata;
		GridLayout glayout;