Bug 122869 Drag a parameter from data explorer view into a table in library, a new parameter is created automatically.
Description:Drag a parameter from data explorer view into a table in library, a new parameter is created automatically. Steps to reproduce: 1. Add a cascading parameter and a table in a library file. 2. Drag a parameter from data explorer view into a table cell in layout editor. 3. Find that a new parameter was added in data explorer view automatically.
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/internal/ui/dialogs/ExpressionTreeSupport.java
else if ( handle instanceof ParameterGroupHandle )
			{
				TreeItem groupItem = createSubTreeItem( topItem,
						DEUtil.getDisplayLabel( handle, false ),
						ReportPlatformUIImages.getImage( handle ),
						true );
				for ( Iterator itor = ( (ParameterGroupHandle) handle ).getParameters( )
						.iterator( ); itor.hasNext( ); )
				{
					ParameterHandle parameter = (ParameterHandle) itor.next( );
					createSubTreeItem( groupItem,
							parameter.getDisplayLabel( ),
							ReportPlatformUIImages.getImage( handle ),
							DEUtil.getExpression( parameter ),
							parameter.getDisplayLabel( ),
							true );
				}
			}
		}
	}
	/**
	 * Create data sets band.Must set Tree before execution.
	 * 
	 */
	public void createDataSetsTree( List dataSetList )
	{
		Assert.isNotNull( tree );
		TreeItem topItem = createTopTreeItem( tree, TREE_ITEM_DATASETS );
		for ( Iterator iterator = dataSetList.iterator( ); iterator.hasNext( ); )
		{