I use a perl script to format the error output of my compiler in a way that can be easily parsed by the error list. This worked fine up to version 1.9 of the error list (which I still use today).
With the more recent versions (since the german localization, 2.0 ?) I get a very strange behaviour: I check the error output in the plugin options and get a display of all included errors and warnings. But in real life, the error list shows just nothing. I have tried to modify my perl script in several ways (output to std out, output to error out, output to both) without any change.
Probably it is related to handling of line's breaks '\n', '\r\n'.
I'll research this during the weekend.