Why does soapUI use so much memory/RAM?

I'm using the open source soapUI 5.1.3 to simply send requests to web services and view responses.  I typically have several projects open.  Even when I'm not using the application (application is in the background, no active requests are being made, etc.), it consistently uses 1g + of memory.  It also seems to build up over time (perhaps things aren't being flushed that should be, memory leak, etc.).

 

I've noticed numerous other posts about memory issues so this seems like a rather serious problem.