BUG: Multiple OpenSSH keys do not all work even though each one works when loaded by itself

[danhswain]

I need to access multiple BitBucket accounts each with their own key.  If I put one OpenSSH key into SourceTree at a time, I can access any of the accounts so long as the key for the account being accessed is the one present in SourceTree.  However, SourceTree DOES allow MULTIPLE keys to be loaded via Tools -> Add SSH Key....  After they are added, you can see the multiple keys in the "SSH Key" field when opening the Tools -> Options dialog.  The keys are there separated by semicolons.  HOWEVER, when doing a test Fetch across the various repos, only one of the keys is honored on the repos where it is present.  SourceTree seems not to ever present more than one key to the server even though more than one key is present.  If I switch the keys around, then the repos for the other key are fetched fine.  Surely this is a bug(?).