virtual [FReply](API\Runtime\SlateCore\Input\FReply) OnParameterItemsDragged ( const [TArray](API\Runtime\Core\Containers\TArray)< [FNiagaraParameterDefinitionsPanelItem](API\Plugins\NiagaraEditor\FNiagaraParameterDefinitionsPane-_1) > & DraggedItems, const [FPointerEvent](API\Runtime\SlateCore\Input\FPointerEvent) & MouseEvent ) const