Size of the FB/Twitter/G+ sharer window

Hi !

Why does a new tab open when I try to share an article from my site on FB/Twitter etc. ?

For exemple, click on one of the logos at the bottom of this page :
https://www.oiseauravage.com/histoires/les-anges-de-loubli

Instead of a whole new tab, I’d like a small new window to open (the “usual” way) when I click on one of the logos to share the article.

Can you help me ? :)
Thanks a lot !