It's a sad fact of life on MathOverflow that sometimes you get an answer (often a good one) that makes you realize you asked the wrong question. We don't seem to have a really established policy on what to do in this situation, and probably we can't really expect to come up with one. Still, I'd feel better if I had a better read on the community's opinion on this matter.

As a jumping off point, let me point out something I just did: * I asked a question about whether a particular statement was true. * A very nice counter-example was posted. * I realized that the counter-example was precisely based around a piece of wiggle room that doesn't exist in my situation, and thus was left with a dilemma. The counter-example perfectly answered the question I had asked, but not the one I should have. * I opted to ask a second question which was almost exactly the same, but had a new hypothesis making the old answer inapplicable. (And, of course, provided links between the questions).

So here's where I ask your collective opinion...did I do right?

I would say you did just the right thing. The alternative, namely to tell the answerer who perfectly answered the question "thank you, but your answer doesn't answer the question I didn't ask" can be fairly annoying.

I agree that you did the right thing here.