Editing nant build files in IDEA shows syntax errors as IDEA assumes it is an ant file. I have a nant build file that I am editing in IDEA (7.0M2)- thinking that as the XSD is specified IDEA will validate against that. But IDEA seems to think its an ant file and is validating as such. Here is part of the file: <?xml version="1.0"?> <project name="MithrasNet" default="solution-rebuild" xmlns="http://nant.sf.net/release/0.85/nant.xsd"> <property name="project.root" value="${directory::get-current-directory()}" /> <include buildfile="include.build"/> The nant xsd file is in the resource cache - it shows as green. But IDEA is saying things like the <include line is invalid - when it works fine. http://www.intellij.net/forums/thread.jspa?forumID=27&threadID=269739#5197710