I think either I found a bug, or just some really odd behavior. My model wouldn't compile, until I deleted a flow and then ctrl-z'd it right back. I have a class with a rapid port and flow to a composite class with a rapid port. At this point, everything compiles and runs correctly. Then I added a class with a 1 to 1 association to the other class. When I try compiling, it displays numerous errors, starting with getIts<classname> isn't defined. Insert whatever class name you want there. I wish I could tell you exactly what the error text was, but now its working. I tried deleting the association, and of course it does compile. I put the association back, and it does not compile. I delete the flow, and it compiled. I put the flow back, and it miraculously still compiles. What happened? All I did was delete something, and press ctrl-Z to undo my delete, leaving it exactly the same. But for some reason, it compiles now.