When launching/compiling a project in FDT, you usually have to wait a short moment for FDT to do a build. During this building process, it generates your TODO lists and performs deep binding. When your project grows and grows (like in my last project with 1000+ of classes), this will take longer and longer. I reached the point of annoyance, since I just wanted to launch and knew that my code was error free. Also, the Flex compiler will tell me if there are errors in my code, so waiting for the FDT build to tell me seems to be a redundant task to me.
So I searched the Eclipse preferences panel and discovered that my solution was just sitting there all the time. Here it is: