No action on "Delete only", fetching new mails (w preselect)

1. active preselect mails on server pop3
2. Get new mails (i.e. from toolbar)
3. select all
4. "Delete Only"
5. "Fetch" (get)

issue: nothing happens; the mails are still there.

this happens with "delete only" AND "select ALL" mails on the server;
(in others word if the "Delete only" is the only action to do, during the session.

i.e. if I have five mails on server, and I set for 3->"Delete Only" and for 2->"fetch and delete" works Ok.

I'm on PEG2 G4 MOS1.4.5 latest ambient build and latest MUI NList_xx classes.

This happens from 6-7 builds till now.