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
* @return validate result
	 */
	protected static boolean handleValidateDataSetColumn(
			DataSetItemModel insertObj, EditPart target )
	{
		if ( handleValidateDataSetColumnDropContainer( target )
				&& DNDUtil.handleValidateTargetCanContainType( target.getModel( ),
						ReportDesignConstants.DATA_ITEM ) )
		{
			
			if ( target.getModel( ) instanceof ModuleHandle )
			{
				return true;
			}
			
			DesignElementHandle handle = (DesignElementHandle) target.getParent( )
					.getModel( );
			if ( handle instanceof ReportItemHandle
					&& ( (ReportItemHandle) handle ).getDataSet( ) == null )
			{
				return true;
			}
			return DEUtil.getDataSetList( handle )
					.contains( insertObj.getParent( ) );
		}
		return false;
	}
	/**
	 * Validates drop target from scalar parameter in data view.
	 *