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
{
			dataSetHandle = ( (ReportItemHandle) handle ).getDataSet( );
		}
		if ( dataSetHandle == null )
		{
			for ( DesignElementHandle elementHandle = handle; elementHandle != null; elementHandle = elementHandle.getContainer( ) )
			{
				if ( elementHandle instanceof ListingHandle
						&& ( dataSetHandle = ( (ListingHandle) elementHandle ).getDataSet( ) ) != null )
				{
					return dataSetHandle;
				}
			}
		}
		return dataSetHandle;
	}
	/**
	 * Get a container that is a ListingHandle that can hold dataset.
	 * 
	 * @param container
	 * @return
	 */
	public static ListingHandle getListingContainer(
			DesignElementHandle container )
	{
		for ( DesignElementHandle elementHandle = container; elementHandle != null; elementHandle = elementHandle.getContainer( ) )
		{
			if ( elementHandle instanceof ListingHandle )
			{
				return (ListingHandle) elementHandle;