This bug was originally marked as duplicate of bug 251825, that is already resolved. This bug is still valid, so this seems to be another bug, but it might be related.
Build: NetBeans IDE 8.1 (Build 201510222201)
VM: Java HotSpot(TM) 64-Bit Server VM, 24.80-b11, Java(TM) SE Runtime Environment, 1.7.0_80-b15
jkmaurya: Tried to open Config.groovy in a grails project
Maximum slowness yet reported was 195416 ms, average is 195416
Created attachment 160112 [details]