"Add widget" buttons duplicate

[JakubChecinski]

I'm not 100% sure it's a bug we need to fix, but dr Frankowski told me to report it just in case

Indicate the dataset
Single files from 0200 nm dataset

To Reproduce
Steps to reproduce the behavior:

1. Load a single file
2. Load another single file
3. For the next few seconds, the "add widget" buttons duplicate
4. After a few seconds, there is only one button and it can be clicked normally

Screenshots
https://imgur.com/bbryCuW

[LemurPwned]

Yes, it is a known bug. However, we do not know how to fix it :( (yet!)
Marking as wontfix for now