I recently found out that I can now use Flash Builder 4 to debug and write code that I started out writting using Flash CS5. This has saved me tremendous amounts of time. However when I make small changes to the canvas in flash CS5. (e.g. added another button to the stage w.o. connecting it to any code. It is just another drawing element at the moment), I find that when I clean and rebuild the target in Flash Builder, the program no longer runs. The program seems like it has become disconected from the canvas / stage. Any time I reference something like stage.framerate, I will get a error saying can not assign null value.
Has anyone had a similar problem, or have any experience on the correct way to work with flash and flash builder. I have been wracking my brain over this for a while. I ended up reverting to previous version that I had saved in Flash CS5. This worked well, untill I tried adding a symbol to the stage.
The base class of my stage is set to Document.as as it should be.