This bug was originally marked as duplicate of bug 218410, that is already resolved. This bug is still valid, so this seems to be another bug, but it might be related.
Build: NetBeans IDE 8.0 Beta (Build 201401141042)
VM: OpenJDK 64-Bit Server VM, 24.79-b02, OpenJDK Runtime Environment, 1.7.0_79-b14
Maximum slowness yet reported was 41485 ms, average is 41485
Created attachment 155501 [details]
Whole IDE seems to blocked by an extremely slow AWT painting.