Web Designer: no popup when downloading a file

I included a file-downloading module into my web portal. I made it under a Server action of the button.

The General Settings are as follows:

When i click Download, the file opens in the browser, on the same page. But I want it to open in a popup that prompts the user to save this file. What do i do wrong? It seems to be a standard behavior, or does the File-Download module open files only in browser?