Redmine

I didn't know that an administrator can access another user's "to me only" query by typing a URL like /queries/123/edit.

I wonder if the behavior should be allowed.

Just tested to edit some random query of another user as admin vs. non-admin. At least I got "permission denied" for the non-admin user. So there are permissions checks. Guess admin is allowed on purpose.

Jon Schell wrote:

to create and save queries

Have a look at https://www.redmine.org/plugins/redmine_impersonate
With that, you can impersonate that user and edit the query he needs to share/create. Might be helpful and from what I've read, you know the user who needs support? So you see a list all queries of that user.