TST: to_html regards empty string labels as repeated labels GH3547
BUG: to_html regards empty string labels as repeated labels GH3547
Merge branch 'GH3547'

* GH3547:
  BUG: to_html regards empty string labels as repeated labels GH3547
  TST: to_html regards empty string labels as repeated labels GH3547
DOC: update RELEASE.rst