To change the number of mailboxes that are displayed on these menus:
Choose Move Menu Setup from the Options menu.
The Move Menu Setup Options dialog box is displayed.
Increase or decrease the number of mailboxes you have recently opened in the "Display up to: Recently visited mailboxes" field.
Click OK or Apply to make the change take effect.
Up to the desired number of mailboxes now appear on the Move menu and the Copy To Mailbox submenu of the Message menu.