EnsemblGenomes queried with non-existent identifier takes a long time to report 'not found'

if you attempt to retrieve a non-existent identifier from the EnsemblGenomes datasource, you have to wait a considerable time before Jalview reports that the identifier couldn't be retrieved (try e.g 'foobar').

Performing a similar query on the Ensembl datasource results in a 'not found' response far more quickly.

this seems to be an upstream issue - waiting on response from Ensembl helpdesk.