sequence ID tooltip not showing during long running retrieval/crossref operations

When retrieving crossreferences for ENA entries with many database crossrefs, moving the mouse over the sequence ID panel can trigger an exception:

Exception in thread "AWT-EventQueue-0" java.util.ConcurrentModificationException
at java.base/java.util.ArrayList.sort(ArrayList.java:1752)
at jalview.io.SequenceAnnotationReport.appendDbRefs(SequenceAnnotationReport.java:548)
at jalview.io.SequenceAnnotationReport.createSequenceAnnotationReport(SequenceAnnotationReport.java:510)
at jalview.io.SequenceAnnotationReport.createTooltipAnnotationReport(SequenceAnnotationReport.java:630)
at jalview.gui.IdPanel.mouseMoved(IdPanel.java:130)


It turns out that the SequenceAnnotationReport code applies an in place sort to the list of database references - causing the exception.

Solution 0: defensive copy prior to sorting for display.
Solution 1: maintain the dbrefs as a sorted list ?
Solution 2: store references indexed by provider, each sorted by accession.

See JAL-3979 for other optimisations