Breakpoints working in MXML files, but not ActionScript files : Flash Builder 4

I am trying to debug the Flex application. I am able to set breakpo开发者_如何学编程ints in mxml file, and application breaks on those breakpoints. But when I set breakpoint in as files, I don't see the breakpoint marker, though in breakpoints window I am shown the line no. And when I start my debugging session, the application does not break at that point.

what could be wrong?

Typically this means that the SWF you are debugging is mis-matched with the code you are attempting to break at. Therefore it may look like it isn't breaking because the line number you specified in the IDE may match a non-executable line number in the built SWF. I suggest making sure to manually delete bin-debug, do a full refresh, then do a clean.

Also, there is a known issue regarding Flash Builder 4 (and Flex Builder 3) where if you connect your computer to multiple monitors, the line-number/breakpoint/error column in the editor will cease to work on any monitor except the one that had the IDE launch to originally. I don't offhand have the Adobe bug page for this, but it's an Eclipse bug in Ganymede and Galileo. I believe it is fixed in Helios, and would expect Flash Builder Burrito to use Helios.

HTH