wonder about 'table maintenance generater'

Hi, gurus

Let me ask you something...

I created a table, and checked table maintenance allowed field.

and then I defined technical diaglog details using table maintenance generater

some header fields text has it's own text value from data element,

but some has just '+'.

why some fields couldn't get it's own text value from data element?

sorry for my poor english.

regards

kyung woo