Bug 119331 Library - name space terminology and behavior
During BIRT 2.0 library feature review meeting the following change was decided. - Change the term namespace to 'prefix' - By default use the library name as the prefix ( namespace ); the dialog to input prefix should be prompted only if hte auto generated prefix is not unique.
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/internal/ui/dnd/InsertInLayoutUtil.java
*/
		public Object getInsertPosition( )
		{
			return null;
		}
		/*
		 * (non-Javadoc)
		 * 
		 * @see org.eclipse.birt.report.designer.internal.ui.dnd.InsertInLayoutUtil.InsertInLayoutRule#insert(java.lang.Object)
		 */
		public void insert( Object object ) throws SemanticException
		{
			Assert.isTrue( object instanceof DataSetItemModel );
			Assert.isTrue( object == dataSetColumn || object == null );
			getGroupContainer( container ).setDataSet( getDataSetHandle( dataSetColumn ) );
			getGroupHandle( container ).setKeyExpr( DEUtil.getExpression( dataSetColumn ) );
		}
		protected DataSetHandle getDataSetHandle( DataSetItemModel model )
		{
			return (DataSetHandle) model.getParent( );
		}
		protected GroupHandle getGroupHandle( Object target )
		{
			DesignElementHandle handle = null;
			if ( target instanceof CellHandle )
			{
				handle = ( (CellHandle) target ).getContainer( ).getContainer( );
			}
			else if ( target instanceof ListBandProxy )
			{