Fix white empty window when checking for file

[Gkiokan]

When you check or download a file form the Serving View the window stays open as empty one.

• [x] Close Window directly after download
• [x] Add Styling to the window

[Gkiokan]

Actually the styling is a bit harder for a blank screen with no source ...
However, as this is just a simple download request I have minimized the opening window to a minimum
and added the autoclose functionality. So it doesn't annoy anymore.