Use this auto-enter calculation:
IF ( IsEmpty ( self ) ; Relatedtable::Field ; // This is your look up function
TextFormatRemove ( self ) // this strips out any formatting should the users copy and paste into the field
) // If
Make sure to clear the "do not replace existing value" check box
I'm thinking you should add an OnObjectModify script trigger pointing to a script that utilizes the TextFormatRemove function.
oh poopy snoopy, Phil beat me to better option (again).
there is a Lookup() function as well as the Lookup auto-enter. perhaps the function can be leverage when needed in an auto-enter calculation?
I usually prefer an additional feature to remove any leading and trailing spaces.
Note that there are some custom functions that can handle more white space characters, such as tabs, etc.
But the simple version is:
Trim( TextFormatRemove ( self ) )
In addition, there is LookUp() function if you need some options for look up.