Ontology editor: allow multiple roots and get all known roots by default
Ontology editor: allow multiple roots and get all known roots by default

htem/CATMAID,fzadow/CATMAID,htem/CATMAID,fzadow/CATMAID,fzadow/CATMAID,fzadow/CATMAID,htem/CATMAID,htem/CATMAID