Awesome, that is just the thing I was looking for - great catch!
This is again a good example for much control FreeCAD offers over just about everything, as a new user (2 weeks now) I am really impressed.
Eventually I noticed my design tree had been messed up by going forth and back from rev0.16 to rev17, the sketches were not attached to the features (mostly pockets) anymore. The final part looked OK but I was not able to change anything, i.e. redo the individual steps. Also my fault because I did not keep enough backup versions.
I last night I redid every step in rev0.16, copying over the sketches (this did save a lot of work) and eventually adding new drawings again.
Today I made another version of my part using different diameter grooves and got some weird confusion with a chamfer, being applied to a wrong edge. As it was the last step in the tree I just re-did it, and hence the drawing did not refer to the right object anymore. I can confirm that I was able to specify the new object the way you described, and most of the dimensions that I had made with the drawing dimensioning workbench did actually survive. Only a few got messed up but that were easy to remove and add again.
Another note, not related to the original drawing issue which is now solved: I would like to get a better understanding of the overall design process, and the differences between rev0.16 and 17. I think I got the design tree thing (mostly working with part design wb in 0.16), and finally got it working to add statements to refer to dimensions between files using a spreadsheet in the base part (I had a stack of different plates with common screw holes that had to fit to each other). It worked but I am not sure if this was the best (easiest) possible approach.
Then, using rev0.17 I learned about the new body/part paradigm, but only found rather sparse information (I saw this viewtopic.php?f=20&t=12373
) on what all that means in practical terms, me being a new user to FreeCAD (some limited previous CAD experience, though).
For example, for creating multi-part objects (boxes, enclosures, stacks) parametrically in 0.17, is there already more detailed documentation? Or anything more detailed on the overall concepts in 0.17? I would appreciate any pointers in this regard, and also offer my help with creating such documentation.