This one had me stumped for a while, since I am a longtime Windows guy. Every now and then you need to run the “-clean” option on the command line to get Flex Builder (née Eclipse) to behave. In OSX the actual application is hidden in an “.app” package, so you have to insert the following in Terminal:
/Applications/Adobe\ Flex\ Builder\ 3/Flex\ Builder.app/Contents/MacOS/FlexBuilder -clean
I am sure this is a big “duh” for Mac people.
