One solution would be to create a Value List using the values of your text field, then create an unstored Calculation field using the calculation:
ValueListItems ( Get ( FileName ) ; "your_value_list" )
Could you tell me howto? I'm trying to figure out how to do this all, but get stuck after te first step
To create the Value List:
Go to File menu > Manage > Value Lists, then click the "New" button. Type Tag_values in the Value List Name field, then select "Use values from field". A dialog window will open. Select your table from the dropdown menu, then select the text field that contains your tags. Then click OK and exit all the dialogs.
To create the Calculation field:
Go to File menu > Manage > Database. Click the Field tab, type Tag_calc in the Field Name field, select "Calculation" in the "Type" dropdown menu, then click the "Create" button. A dialog window will open. Enter the following calculation:
ValueListItems ( Get ( FileName ) ; "Tag_values" )
Select "Text" in the "Calculation result" dropdown menu, then click the "Storage Options" button and select "Do not store calculation results", then click OK and exit all the dialogs.
Go to Layout Mode and put the Tag_calc field on your layout. Enlarge the field so that it's big enough to display as many tags as you need.
If you follow the above steps, it should work.
(Note: When you enter a new tag in the text field, it won't appear in the Tag_calc field until the window is refreshed. To refresh the window, you can simply navigate to another record, or go to the Records menu > Refresh Window.)