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.core/src/org/eclipse/birt/report/designer/util/DEUtil.java
*            the handle of the elementIt should be a ReportItemHandle or a
	 *            GroupHandle
	 * @param column
	 *            the column to add
	 * @param inForce
	 *            true to add the column with duplicated expression,or false not
	 *            to do
	 * 
	 * @return the handle of the binding column,or null if failed
	 */
	public static ComputedColumnHandle addColumn( DesignElementHandle handle,
			ComputedColumn column, boolean inForce ) throws SemanticException
	{
		Assert.isLegal( handle instanceof ReportItemHandle
				|| handle instanceof GroupHandle );
		if ( handle instanceof GroupHandle )
		{
			return ( (GroupHandle) handle ).addColumnBinding( column, inForce );
		}
		return ( (ReportItemHandle) handle ).addColumnBinding( column, inForce );
	}
	/**
	 * Returns the binding column iterator of the given element
	 * 
	 * @param handle
	 *            the handle of the element. It should be a ReportItemHandle or
	 *            a GroupHandle,or an empty iterator will be returned.
	 * @return the iterator of binding columns
	 */
	public static Iterator getBindingColumnIterator( DesignElementHandle handle )