Print.

Synchronise folders

Save as...

Toggle threaded display

Go to next unread mail.

Go to other folder…

Show message source

Toggles the message view panel visibility. When invisible, Message List expands itself to fill the full window height and  more summary lines are displayed

Get mail from current account

Get mail from all accounts

Compose a new message

Reply

Reply to all

Reply to mailing list

Forward message

Move...

Empty all Trash folders

Mark message

Toggles menu bar visibility

Paste