Table field heading not displayed in SM30

Hi,

I have created a Z table and custom data types, to assign to table fields. But when i see the table in SM30, the fields are displayed as '+' and no field label are being displayed. Even after making entry to the table, when i check in SE11, there also it's not showing Field label, only field names are being shown. Do i need to do any changes? Please help.

Regards,

Anubhab