Can't set tab order for text fields in Interface Builder

I'm trying to set tab orders in Interface Builder but am having problems.

I have set up the tab orders in Interface Builder using the nextKeyField attribute, but when I test the tab order, I still jump to the text label fields even though they are not editable.

How do I fix the tab order so that I only go to the following text fields (for data entry) when I tab through the window?

Thanks in advance.