Outlook vs Sharepoint

A little thing, but an annoying one.  Both Outlook and Sharepoint cache used e-mail addresses, even when you've entered the address incorrectly; these then appear as auto-complete options on new e-mails.  To delete incorrect or unwanted entries from the auto-complete list:

In Outlook:
Open a new e-mail.
Start typing an address.  An auto-complete list will appear.
Use keyboard arrows or mouse to highlight the offending entry.
Click the X at the right-hand side of the entry to delete.

In Sharepoint:
Similar procedure, except that you cannot use the mouse, or the process fails.
Open a new e-mail.
Start typing an address.  An auto-complete list will appear.
Use the keyboard arrows to highlight the offending entry.
Use the Delete key to delete the entry.