(in the screenshot you can see it's greyed out and when you try and click it, it says "no targets available")
In 1.3 patch notes I believe it was intended to work with squadsight but seems to be bugged again in 1.4.
Mods I'm running:
- Yet Another F1
Blackmarket Usage
Robojumper's Squad Select: LW2 + Various Speed-ups
Quick Reload
Instant Loot
New Target Icons
Show Defense in Armory
Quick Soldier info
Show Infil % in squad select
Gotcha Again
LW2: Showmetheskills revived
Stop Wasting my Time
Evac All
Perfect Information
Instant Avenger menus
No Drop-down lists