I wrote a CAD viewer app on flash 7.2 / 8 and definitely avoided the flash IDE as much as possible since it wasn't a particularly good IDE. I had just two frames on the stage, one for a loading message, one for the app ui container, with all behavior and ui creation in actionscript files, which I edited with an external editor. I moved up to the flex sdk eventually, completely abandoning the flash ide and not even using the flex ui framework (since it was too bloated). In the end though, the entire CAD viewer (essentially an SVG subset parsing and rendering engine with some ui decorations) was a 91 kb .swf, including the assets (like custom mouse pointers). That was the mixed blessing of flash: amazing abilities locked into a compromised platform.