Just in case anyone is (re)searching NetBeans compatibility on OpenBSD, other reports have been posted to
misc@ about similar square characters being displayed in the output window:
http://marc.info/?t=124471991100002&r=1&w=2
Remember,
http://marc.info/ is a wonderful resource for the Open Source community. OpenBSD users should consider this as an authoritative resource on par with the manpages. Use them both, & use them often.
...& flossing after every meal is good too.