Fields that are greyed out in ERD?

[efpw]

I am getting some erratic behaviour and don't understand why..

I have a feeling that it is my ERD structure that is at fault and some of the fields in question are greyed out, as seen in the attached.

Can anyone explain why they might be greyed out?

Thx

Edited April 25, 2010 by Guest

[efen]

Because they`are defined as containers, summaries, timestamps that can't be used in relationships

[efpw]

Oh, I see!

Thanks for taking the trouble to answer a rather simple question. I thought that it might be highlighting a structural problem!

efpw

[comment]

Timestamps??