Save online updates the wrong score when switching tabs during upload
The 'source' tag in the 2nd score is replaced/updated with the one from the 1st (the "Save online"ed one), and then on "Save online"ing that 2nd it updates/overwrites the 1st.
How to reproduce
1) Open 2 scores in MuseScore 2.2.1 (possibly earlier)
2) Save the 1st one online
3) While saving is in progress, switch to the 2nd score
4) The 2nd score is updated with the 1st one's source URL
5) When saving the 2nd score, it shows the score information of the 1st andwill overwrite the 1st if you "Save".
This happened to me once with 2.2.1.
I did not have time to test myself to see how repeatable this is, but am working off the steps reported by https://musescore.org/en/node/271712
1) Get the URL off of musescore.com for the score that should be uploaded to (2nd score in above example)
2) File -> Score Properties -> source (paste the URL of the score and save)
As seen in