I can't modify/delete test step fields (Zephyr)

[Axel Nardin]

Hello, 

I have a problem with Zephyr. First, I create a new Issue (Issue Type : Test), with one Test Step. Then I have this : 

Everything is good here. But I can only create it, if I want to modify this field or delete it ("aaa" fields), I can't : 

I don't know where the problem come from. I'm admin, with full access on this project (TEST). For information in an other project, I can modify and delete test steps. We checked the permissions, and we don't find where is the problem.

Thank for your answers !

Axel