java.lang.NullPointerException at org.netbeans.spi.looks.Look$ListenerCache.removeListener(Look.java:675) at org.netbeans.spi.looks.Look.removeLookListener(Look.java:568) at org.netbeans.spi.looks.ProxyLook.removeLookListener(ProxyLook.java:1166) at org.netbeans.spi.looks.ProxyLook.removeLookListener(ProxyLook.java:1166) at org.netbeans.spi.looks.ProxyLook.removeLookListener(ProxyLook.java:1166) at org.netbeans.spi.looks.AccessorImpl.removeLookListener(AccessorImpl.java:36) at org.netbeans.api.nodes2looks.LookNode$FirerImpl.run(LookNode.java:842) at org.openide.util.Utilities$ActiveQueue.run(Utilities.java:2443) [catch] at java.lang.Thread.run(Thread.java:534)