Playlist downloading problem

Hey what's up gays,

My name is Houssem,

Recently I deleted the extension because it didn't do any thing when I click on download a playlist), so I reinstalled it, but it behave differently that time : when I want to download a playlist it asks me to chose a destination file and then it download all the videos at the same time (You know the number of videos in a playlist !!!) which decrease tremendously my internet speed and also it takes much more time than downloading file by file.

Is it a new feature?

My browser is Firefox version 50.1.0 the latest version.

Savefrom.net helper version is 6.20.

Thank you.