Rated 5 out of 5 stars

no trojan at all, you can have the source code of dwmxpcom.dll here:
http://www.sleepingcats.org/svn/DwmXPCOM/

also, this file and its source code have been reviewed by the editors of Mozilla.

This review is for a previous version of the add-on (0.1.6.9d).