How to always launch main application file in FDT Flex Project

If you are used to using Flash Builder and you use command + f11 to debug your app then you will most likely want to change the settings in eclipse if you start using FDT. By default FDT launches and compiles any open file that you are editing at the time. For Flex development this is most likely not the setting you want. Simply go to FDT > Preferences > Run/Debug > Launching > and under Launch Operations make sure Always Launch Previously Selected Application is selected.