Cannot use Select-All and then use the delete shortcut on the keyboard to delete messages. The icon on the toolbar is also greyed out. Only way is to go to File -> Delete Message.
16 years ago
wfm with 2002072204/Win2K, pop account. First I set focus to thread pane (this is another bug), then I can delete using Select All, Del key.
this worksforme with build 2002-10-09-20, Windows 2000 with POP3 and IMAP.