Bulk export processes continue processing after the user close the browser window.

Steps to reproduce:

1. Search for 500 issues
2. Select Xporter for JIRA to export them
3. Select the Issue List Excel template and Excel output format.
4. Let the process start and after the progress bar start presenting values > 0% close the window.
5. If you go to a JAVA profiler, you can see that the Xporter thread is still running.

We need to create a way to avoid these scenarios.