Just a quickie, but I thought I’d share this.  Basically all of a sudden Flex Builder stopped showing me errors in the problems panel.  I couldn’t work out what on earth was going on, I was being show the visible warnings on the actual lines of code that were wrong when I was looking at the file and I was getting the alert box pop up to let me know there was an error when I compiled but nada in the problems panel.  I paniced and reinstalled flex builder.  That didn’t work, I went through everything and eventually found the problem.

A few days ago I had loads of projects I was working on and so I started using working sets to limit the number of projects I was seeing in the resources panel.  Somehow the problems panel reset itself to filter the error reporting to just the working set selected.  I didn’t see this and that is when I stopped getting my error reporting.

Solution, click on the filter button to the right of the problems panel.  Select the “on any element” radio button and then ok.  Should sort the problem.