Can't add new task in project template

Hi,
I can’t add task in project template. I can create a new project template. When i click on add task, a window opens.
But in this one when i click on add button nothing happened
Can you help me ?
Thanks
(Sorry for my english, i am not an english speaker …)

This is happening to me too. Version 7.7.9

How did you solve it?

I didn’t solve it. Same problem in last version 7.9.1

In fact, i can add task in template project when i go in details of project.