Running code in parallel with only one Zeppelin instance

Hi,

We are trying to run some code in parallel using Zeppelin two notebooks in two Zeppelin UI open in two tabs in the browser login with the same user.

However, even if we run both notebooks at the same time, one of them gets executed and the other one waits until the first one finishes to start running.

Is it normal behavior of Zeppelin? Is there any way it supports parallel execution of notebooks with the same user?

Thanks.