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