Thank you for the clarification. Yes, after examining the functionality further, the design constraint you mentioned does seem to be working as designed. I was trying to add both a maven and ant tool installation to an individual build environment b/c of some automation projects we have built. We have an ant build.xml file that performs some work, after which it "exec's" maven explicitly to finish the work. For this reason, I was wanting to define both the ant and maven installation.
We have found some alternative ways to ensure our approach works, so either:
A) The current design constraint (can't have ant and maven builder as part of a single installation) is valid, and this ticket should be closed.
B) The current design constraint is artificial, and thus could be relaxed...which would mean this ticket really becomes a feature enhancement.
With the tight integration between ant and maven, I would be interested to know if option B is possible.