This bug was originally marked as duplicate of bug 187486, that is already resolved. This bug is still valid, so this seems to be another bug, but it might be related.
Build: NetBeans IDE Dev (Build 201704070002)
VM: Java HotSpot(TM) 64-Bit Server VM, 25.60-b23, Java(TM) SE Runtime Environment, 1.8.0_60-b27
OS: Windows 10
GUEST: Running Code Completion
Maximum slowness yet reported was 13029 ms, average is 13029
Created attachment 164071 [details]