Setting the keys for exiting a field
You can specify for a field whether it’s possible to go to the next field with the Tab key, Return key, Enter key, or any combination of these three keys. Setting more keys may make data entry easier, particularly for fields where you don’t need to enter tab characters or return characters.
Note  Most Windows keyboards contain two Enter keys, one in the main part of the keyboard and one in the numeric keypad. In FileMaker Pro, the Enter key in the main part of the keyboard behaves as the Return key.
To set the keys that may be used to exit a field:
In Layout mode, select one or more fields. Or, to specify attributes for fields you add later, start with no fields selected.
For more information, see Selecting objects.
Click Inspector Inspector button in the layout bar, then click Data.
In the Behavior area, for Go to next object using, select the keys you want to use for exiting fields.
Note  When the Tab key is set to go to the next field, you can still enter a tab character into a field by pressing Ctrl+Tab (Windows) or Option-Tab (OS X).
Related topics 
Setting the tab order for data entry