Source editor blames current source file for errors in other files

If while processing A.x10, a reference to B.x10 is encountered, the compiler front end processes B.x10, and may issue messages regarding various kinds of errors on B.x10.

If the compiler front-end was invoked on behalf of the source editor, such errors will actually be flagged on A.x10, since the CompilerDelegate uses an anonymous AbstractErrorQueue that doesn't differentiate errors on distinct files. It should really only report errors on the file for which it was intended (since the CompilerDelegate is responsible for a single source file, the one in the open source editor).