Refactor toolbar into its own widget to improve extensibility for further datatypes.
Gerrit change 49827 and Gerrit change 50151 merged.
This has been fixed. I just saw that there is some DOM left though. Just filed a new bug for this as bug 45673 since this is rather trivial compared to this major bug.
Gerrit change #50911 belongs to here.
Verified in Wikidata demo sprint 34