Missing folding icon in front of class definition

Hi all,

I am new user of idea 2023.2.2 (Community Edition) on ubuntu 22.04 running on WSL2, using to learn java following a tutorial.

I don't see any folding icon in front of class definition, 

whereas folding icon appear in the gutter in front ot method definition.

The issue is there wether I use classical or new UI

Does someone know how to make folding icon also show up in front of class definition and not only in front of method definition ?

Thanks !