Having the same issue with 8.0.2 when a project has JS resources I tracked it down in my case to a problem with the javascript2 editor module which has been updated over the original version shipping with netbeans 8.0.2.
I simply solved it by removing the updated module.
On Linux:
rm ~/.netbeans/8.0.2/modules/org-netbeans-modules-javascript2-editor.jar
However, after letting the netbeans updater download the module a second time, the problem didn’t appear again.
In Netbeans 8.1, the location of this file is at:
ide/modules/org-netbeans-modules-javascript2-editor.jar.