MSA Editor: save chosen sequences for PWA

1) Open "samples/CLUSTALW/COI.aln"
2) Activate the PWA tab.
3) Click "Phaneroptera_falcata" sequence name on the MSA Editor and click the first ">" button.
4) Click "Isophya_altaica_EF540820" sequence name on the MSA Editor and click the second ">" button.
5) Deactivate the PWA tab.
6) Activate the PWA tab.
Expected: chosen sequences and their order are saved.
Actual: "Isophya_altaica_EF540820" became first. "Phaneroptera_falcata" disappeared.