java.lang.AssertionError: CloneableEditorSupport.getOpenedPanes() must be called from AWT thread only
   at org.openide.text.CloneableEditorSupport.getOpenedPanes(CloneableEditorSupport.java:1122)
   at ramos.filednd.Installer.listenToDndOnPane(Installer.java:120)
   at ramos.filednd.Installer.restored(Installer.java:93)
   at org.netbeans.core.startup.NbInstaller.loadCode(NbInstaller.java:426)
   at org.netbeans.core.startup.NbInstaller.load(NbInstaller.java:366)
   at org.netbeans.ModuleManager.enable(ModuleManager.java:1080)
   at org.netbeans.core.startup.ModuleList.installNew(ModuleList.java:339)
   at org.netbeans.core.startup.ModuleList.access$2500(ModuleList.java:117)
   at org.netbeans.core.startup.ModuleList$Listener.stepEnable(ModuleList.java:1415)
   at org.netbeans.core.startup.ModuleList$Listener.access$1500(ModuleList.java:1007)
   at org.netbeans.core.startup.ModuleList$Listener$1.run(ModuleList.java:1237)
   at org.openide.filesystems.EventControl.runAtomicAction(EventControl.java:127)
   at org.openide.filesystems.FileSystem.runAtomicAction(FileSystem.java:566)
   at org.netbeans.core.startup.ModuleList$Listener.run(ModuleList.java:1213)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1424)
   at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:1973)