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
{
			createNativeObjectsTree( );
		}
		if ( filter( TREE_NAME_BIRT_OBJECTS, filterList ) )
		{
			createBirtObjectsTree( );
		}
		if ( filter( TREE_NAME_OPERATORS, filterList ) )
		{
			createOperatorsTree( );
		}
	}
	/**
	 * Filters the tree name, given the filter list.
	 * 
	 * @param treeName
	 *            the tree name to be filtered.
	 * @param filters
	 *            the filter list.
	 * @return true if the tree name passes the filter list.
	 */
	private boolean filter( String treeName, List filters )
	{
		if ( filters == null )
		{
			return true;
		}
		for ( Iterator iter = filters.iterator( ); iter.hasNext( ); )
		{
			Object obj = iter.next( );