The last sequence is selected unexpectedly if you click on an empty space below the names list

Scenario:

1. Open "COI.aln" sample alignment.
2. Select sequence "Roeseliana_roeseli".
   Expected result: "Roeseliana_roeseli" is selected.
3. Click with the mouse on the empty space below the sequences names.
   Expected result: the selection has disappeared.
   Actual result: the last sequence "Hetrodes_pupus_EF540832" is selected.

Also reproducible in release 33.