A Subtle Difference Between GROUP and GROUP FIELD
There is one subtle difference between a GROUP and a GROUP FIELD that you may want to keep in mind. When a group in the Decode Pane is selected, the complete range of bits or bytes that comprise the group in the Binary, Radix and Character Panes is selected. By contrast, when you select a group field, only the bits or bytes that comprise the field are highlighted. To a user viewing the Decode Pane, however, a group and a group field look very similar. In fact the following would look identical except for the highlighted bytes.
GROUP FIELD grp_fld (Fixed 0 Bits) (Constant "X") "Data"
GROUP grp "Data: X"
The lesson to be learned here is that it is a good idea to maintain a clear distinction between groups and group fields by displaying some "real" formatted data for a group field and avoiding colons in group tags. This is an unlikely lesson because it is unlikely that you would find reason to use GROUP FIELD and GROUP in a confusing way to start with (unless you happen to use GROUP FIELD where GROUP is more appropriate).