Bug 120503 Cascading Parameter can not drop into layout
Details: Cascading Parameter can not drop into layout Step: 1.Open a report design and Create a Sample Data Source and data set by "select * from CLASSICMODELS.CUSTOMERS" 2.New a cascading parameter and create CUSTOMERSNUMBER and CUSTOMERSNAME in parameter named number and name. Press OK 3.Drop parameter name into layout. Actual results: The parameter in Cascading Parameter Group can not drop to layout
UI/org.eclipse.birt.report.designer.ui.lib/src/org/eclipse/birt/report/designer/internal/lib/views/outline/LibraryOutlinePage.java
new DropTypeConstraint( ParameterHandle.class,
						ParameterGroupHandle.class,
						true ) );
		dropListener.addDropConstraint( ParameterGroupHandle.class,
				new DropTypeConstraint( Object.class,
						ParameterGroupHandle.class,
						false ) );
		dropListener.addDropConstraint( CascadingParameterGroupHandle.class,
				new IDropConstraint( ) {
					public int validate( Object transfer, Object target )
					{
						return RESULT_NO;
					}
				} );
		
		dropListener.addDropConstraint( ScalarParameterHandle.class,
				new IDropConstraint( ) {
					public int validate( Object transfer, Object target )
					{
						ScalarParameterHandle targetParameter = (ScalarParameterHandle) target;
						if ( targetParameter.getContainer( ) instanceof CascadingParameterGroupHandle )
							return RESULT_NO;
						return RESULT_UNKNOW;
					}
				} );
		
		getTreeViewer( ).addDropSupport( ops, transfers, dropListener );
	}
}