title: prevent jupyterlab from automatically starting new session for all open tabs
body: <p>I shut down all kernels and close jupyterlab in the browser, but when I open it again it starts a session, and a kernel, for all opened notebooks</p>
  <p>I'd followed the code and found that in <a href="https://github.com/jupyter/notebook/blob/57db70979b677b0c47cbecfbfbc3ba5b359bc0b3/notebook/static/notebook/js/notebook.js" rel="noreferrer">jupyterlab notebook code</a> the start session function calls (POST /api/sessions) on notebook load if there is not any running kernel for the current notebook. and the API <a href="https://github.com/jupyter/notebook/blob/8cd9a5f78af88c7eaf5affb73e79875200536fbd/notebook/services/sessions/sessionmanager.py#L92" rel="noreferrer">creates a session</a> and also <a href="https://github.com/jupyter/notebook/blob/8cd9a5f78af88c7eaf5affb73e79875200536fbd/notebook/services/sessions/sessionmanager.py#L111" rel="noreferrer">starts a kernel</a>.</p>
  <p>I can't find any config for stopping this action in jupyter configs or jupyterlab settings (settings -&gt; advanced settings editor)</p>