I have seen a report whereas the linking of the subreport is based on an ID field but also shows a parameter field in the linking dialog at the bottom. This parameter field is a parameter field setup in the subreport. But when I try to do the same for my report, here is what I do:
1) Right-click the subreport from the main report
2) Select "Change Subreport Links"
3) Move over the ID of the primary table that the main report is based off of
4) Try to tell the drop down at the bottom to use a parameter field I setup in the subreport
The problem is, I only get one value in the drop down for the parameter to use which is ?Pm-tablename.recordid
Where is the option to select that param I created in the subreport? Also, the checkbox for "select data in subreport based on field" is not checked...and I really don't understand why you would use that anyway.