CPU at 100% with groovy code

I'm trying to work with a groovy project that has a single code file.  Every time I open this project and open the code file, CPU immediately climbs to 100% and stays there for as long as the code file is open (I'm not actually running the code).  If I close the code file, or change focus by opening the Settings dialog or something else, CPU usage drops to 5% or so.  The code file has code for opening an xml file and parsing through the elements using XmlSlurper.  There are 4 levels of embedded for-each loops.  If I comment out the two innermost loops, CPU usage drops to normal.  Why would IntelliJ be so busy just by having a code file open?  Including spacing, there's only around 75 lines of code in total.