Bug 145991 [Regression]Invalid data set should not be allowed to drag or "Insert in layout"
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/DataSetHandle.java
super( element, prop );
		}
		/**
		 * Constructs the handle for a top-level property with the given element
		 * handle and property name.
		 * 
		 * @param element
		 *            a handle to a report element
		 * @param propName
		 *            the name of the property
		 */
		public DataSetParametersPropertyHandle( DesignElementHandle element,
				String propName )
		{
			super( element, propName );
		}
		/*
		 * (non-Javadoc)
		 * 
		 * @see org.eclipse.birt.report.model.api.SimpleValueHandle#removeItem(int)
		 */
		public void removeItem( int posn ) throws PropertyValueException
		{
			DataSetParameterHandle paramHandle = (DataSetParameterHandle) getAt( posn );
			DataSetParameter param = (DataSetParameter) paramHandle
					.getStructure( );
			getModule( ).getActivityStack( ).startTrans( );
			try
			{
				super.removeItem( posn );