Where would the cursor be at the time you pressed "return"?
What mode are you in? Find mode I presume?
Are any of your fields text fields where the user might enter multiple lines of text?
The OnKeystroke script trigger can be set up to run a script from the Layout Setup... dialog. If the user is in Find mode at the time you want this to take place, you can enable the script trigger to only "fire" if the database is in Find Mode.
Your script might look like this:
IF [ code ( Get ( TriggerKeystroke ) ) = 13 // 13 is code for the return key]
Perform Find 
Exit Script [false]