ideajoin not working

[aus10code]

This is probably user error but I've tried many things.

below is my .ideavimrc

set surround
set ideajoin

I've tried simple string joins in c# and javascript with no success. It just does simple join

let a = "hello" 
    + "world";

turns into

let a = "hello" + "world";

in :actionlist I do not see anything about ideajoin

[AlexPl292]

Could you please check if it works with the default IDE "join lines" action? If it doesn't, this means that this one join isn't implemented for the language and it's needed to file an issue for them.

[aus10code]

when using Ctrl + Shift + J

into this

this is C# btw

[citizenmatt]

C# doesn't support the smart line join feature, and will do a simple textual join instead (although it will handle whitespace). I've added a feature request for Rider to implement this, as it would be very useful! RIDER-74401

[bad4iz]

javascript and css and md .....and a lot of other things that I didn’t open, nothing works.
Ctrl + Shift + J .it doesn't work either