If you have multiple tabs open in Okular, all tabs get closed without confirmation when clicking on the close button of the window. There is no option at the moment to configure such a behavior.

It happens on a quite regular basis that I click the close button of the window instead of the opened tab. If I have multiple tabs open at this moment, my view is lost. It would be more convenient if Okular would ask for confirmation whether the user really wants to close all tabs when multiple tabs are opened.

Reproducible: Always

Steps to Reproduce:
(1) Open multiple document tabs in Okular (option `Open new files in tabs' must be checked in the settings before).
(2) Click on the window close button.

Actual Results:  
Okular with all tabs closes.

Expected Results:  
Okular should ask for confirmation whether the user really wants to close X tabs.