Please see my comment to the question. No, stack panel is not analogous to wrap panel, not at all. Its behavior is quite different (and quite useful; frankly, if you are using wrap panels, I bet many users do not quite understand how to use your UI; I would call it "lazy panel"
). It's easier to sit down and try out to see what it does.
Generally, the questions like that are very fruitless. Sit down and try some controls, panels, etc. This is easy enough to do. Each experiment will take few minutes; overall, this is much more effective that asking and answering it here.