When using getVisitorProfilePopup widget with custom segment filter and there is no visitor found error occurs:
Key "lastVisits" for array with keys "" does not exist in "@Live/getVisitorProfilePopup.twig" at line 2
Thanks for suggestion! I've fixed it in: https://github.com/piwik/piwik/commit/2607314aaf1d57cb9e413b9604a842b153cb87be
I haven't merged your pull request because the diff of this pull request is quite long, and for safety I prefer to see only the logic that changed.