If the user tried dropping a file onto the paperless-ngx UI, but the page itself had scrolled down a bit, the overlay would have scrolled together with the page.
This commit makes the overlay fixed to the viewport, independent from the scroll position.
This one-word commit was done directly through the GitHub web interface.
If desired, we could also replace spaces with [Box-drawing characters](https://en.wikipedia.org/wiki/Box-drawing_character), like this:
```
🗁 Documents folder
├─🗁 2019/ # By Year
│ └─🗁 My bank/
│ ├─🗎 Statement January.pdf
│ └─🗎 Statement February.pdf
└─🗁 Insurances/ # Insurances
├─🗁 Healthcare 123/
│ ├─🗎 2022-01-01 Statement January.pdf
│ ├─🗎 2022-02-02 Letter.pdf
│ └─🗎 2022-02-03 Letter.pdf
└─🗁 Dental 456/
└─🗎 2021-12-01 New Conditions.pdf
```
But rendering this with proper fixed-width characters can be troublesome on some systems.
Denilson Sá MaiaandGitHub