Taxon selector does not always provide genus-level dropdown options

[sacrevert]

I do not know what the sequence is, but sometimes clicking in the taxon selector does result in the expected highlighting of the specific epithet and the dropdown of all the names matching the genus, and sometimes it doesn't. See below screenshots for constrasting examples.

Works

Doesn't work

Assume this is one for @japonicus

[japonicus]

I think the list is being expanded when there is only a single match for the query string and not if more than one entry matches, i.e. Lamum album also has L. album var maculatum whereas Lamium confertum has only a single match.

This is inconsistent, it would be better if list expansion happened always unless the range of available choices was too great.

As there are a couple of other minor formatting bugs with the taxon picker, I'll package everything together in a couple of weeks once all the tweaks are complete.