Dear Maintainer,

when adding a second download of a file which is secured by HTTP AUTH,
kget becomes unresponsible until the first file is finished.

Steps to reproduce:

1. Download a file which is secured by HTTP AUTH
2. Choose to store the password permanently
3. Try to add a second secured file by clicking on "New download"

Oberservation:

After copying the URL into the address field, the dialog "New download"
does not accept anymore input. It is not possible to click on a button,
edit the address line or close the window. When the first download is
finished, the problem is gone.

This does not happen with unsecured HTTP downloads.