Cannot create new "Set" for my score on musescore.com
User has "pro" account; User is logged in; User does not have any "set" created yet; user has at least one score.
1. Open https://musescore.com/my-scores
2. click next to any of scores (for pop-up menu), select "add to/remove from set"
3. Modal form appears notifying user that he does not have any set yet. Button "Create new set" is available
4. User presses "Create new set"
System process with new set creation
Nothing happens (JS error in console: attached)