Bug 167545 Copy a cascading parameter group and paste it to another parameter group causes an exception thrown
Steps to reproduce: 1.Copy a cascading parameter group using short cut key "Ctrl+x"/"Ctrl+c", or choosing context menu "Cut"/"Copy"; 2.Paste it to another parameter group using short cut key "Ctrl+v", or choosing context menu "Paste"; Expected result: The source one is pasted in the destination. Actual result: An exception thrown org.eclipse.birt.report.model.api.command.ContentException: The Cascading Parameter Group("Source") is not allowed in the slot (parameters) of Parameter Group("Destination").
UI/org.eclipse.birt.report.designer.core/src/org/eclipse/birt/report/designer/util/DEUtil.java
* 
	 * @param handle
	 *            DimensionHandle of model to keep the measure and units.
	 * @return The pixel value.
	 */
	public static double convertoToPixel( Object handle )
	{
		return convertToPixel( handle, 0 );
	}
	/**
	 * Transform other units to pixel.
	 * 
	 * @param object
	 *            model to keep the measure and units.
	 * @param fontSize
	 *            the parent font size.
	 * @return The pixel value.
	 */
	public static double convertToPixel( Object object, int fontSize )
	{
		double px = 0;
		double measure = 0;
		String units = ""; 
		if ( object instanceof DimensionValue )
		{
			DimensionValue dimension = (DimensionValue) object;
			measure = dimension.getMeasure( );
			units = dimension.getUnits( );
		}
		else if ( object instanceof DimensionHandle )