Flex / MXML: Goto declaration doesn't work (Maia #10338)

I've upgraded to Maia #10338 (OS X 10.5.7). Now within an <mx:Script> of a MXML is not possible to use the command "goto declaration" (CMD+B). All mxml tags work fine, it concerns only ActionScript within <mx:Script>. Any idea?

-Jens