java.lang.ClassNotFoundException: org.netbeans.spi.java.project.support.ui.PackageViewChildren$PackageNode
        at java.net.URLClassLoader$1.run(URLClassLoader.java:200)
        at java.security.AccessController.doPrivileged(AccessController.java:0)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:252)
Caused: java.lang.ClassNotFoundException: org.netbeans.spi.java.project.support.ui.PackageViewChildren$PackageNode starting from ModuleCL@167c6fd[org.netbeans.modules.python.project] with possible defining loaders null and declared parents [ModuleCL@144b9ff[org.openide.actions], ModuleCL@196de29[org.openidex.util], ModuleCL@1af4309[org.netbeans.modules.projectuiapi], org.netbeans.MainImpl$BootClassLoader@14ed9ff, ModuleCL@13af084[org.jdesktop.layout], ModuleCL@1ba92db[org.netbeans.modules.project.ant], ModuleCL@1286b10[org.netbeans.modules.gsfpath.api], ModuleCL@107f742[org.openide.windows], ModuleCL@1a02097[org.netbeans.modules.projectapi], ModuleCL@1505258[org.netbeans.modules.queries], ...10 more]
        at org.netbeans.ProxyClassLoader.loadClass(ProxyClassLoader.java:261)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:252)
        at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:320)
        at java.lang.Class.forName0(Class.java:0)
        at java.lang.Class.forName(Class.java:247)
        at java.awt.datatransfer.DataFlavor.tryToLoadClass(DataFlavor.java:119)
        at java.awt.datatransfer.DataFlavor.initialize(DataFlavor.java:445)
        at java.awt.datatransfer.DataFlavor.<init>(DataFlavor.java:381)
        at org.netbeans.modules.python.project.ui.PackageViewChildren$PackageTransferable.<init>(PackageViewChildren.java:1182)
Caused: java.lang.AssertionError: java.lang.ClassNotFoundException: org.netbeans.spi.java.project.support.ui.PackageViewChildren$PackageNode starting from ModuleCL@167c6fd[org.netbeans.modules.python.project] with possible defining loaders null and declared parents [ModuleCL@144b9ff[org.openide.actions], ModuleCL@196de29[org.openidex.util], ModuleCL@1af4309[org.netbeans.modules.projectuiapi], org.netbeans.MainImpl$BootClassLoader@14ed9ff, ModuleCL@13af084[org.jdesktop.layout], ModuleCL@1ba92db[org.netbeans.modules.project.ant], ModuleCL@1286b10[org.netbeans.modules.gsfpath.api], ModuleCL@107f742[org.openide.windows], ModuleCL@1a02097[org.netbeans.modules.projectapi], ModuleCL@1505258[org.netbeans.modules.queries], ...10 more]
        at org.netbeans.modules.python.project.ui.PackageViewChildren$PackageNode.clipboardCut(PackageViewChildren.java:714)
        at org.openide.nodes.FilterNode.clipboardCut(FilterNode.java:646)
        at org.openide.explorer.view.DragDropUtilities.getNodeTransferable(DragDropUtilities.java:132)
        at org.openide.explorer.view.ExplorerDragSupport.dragGestureRecognized(ExplorerDragSupport.java:135)
        at org.openide.explorer.view.TreeViewDragSupport.dragGestureRecognized(TreeViewDragSupport.java:91)
        at java.awt.dnd.DragGestureRecognizer.fireDragGestureRecognized(DragGestureRecognizer.java:339)
        at sun.awt.X11.XMouseDragGestureRecognizer.mouseDragged(XMouseDragGestureRecognizer.java:202)
        at java.awt.AWTEventMulticaster.mouseDragged(AWTEventMulticaster.java:303)
        at java.awt.AWTEventMulticaster.mouseDragged(AWTEventMulticaster.java:302)
        at java.awt.AWTEventMulticaster.mouseDragged(AWTEventMulticaster.java:302)
        at java.awt.Component.processMouseMotionEvent(Component.java:6311)
        at javax.swing.JComponent.processMouseMotionEvent(JComponent.java:3285)
        at java.awt.Component.processEvent(Component.java:6032)
        at java.awt.Container.processEvent(Container.java:2041)
        at java.awt.Component.dispatchEventImpl(Component.java:4630)
        at java.awt.Container.dispatchEventImpl(Container.java:2099)
        at java.awt.Component.dispatchEvent(Component.java:4460)
        at java.awt.LightweightDispatcher.retargetMouseEvent(LightweightDispatcher.java:4574)
        at java.awt.LightweightDispatcher.processMouseEvent(LightweightDispatcher.java:4255)
        at java.awt.LightweightDispatcher.dispatchEvent(LightweightDispatcher.java:4168)
        at java.awt.Container.dispatchEventImpl(Container.java:2085)
        at java.awt.Window.dispatchEventImpl(Window.java:2475)
        at java.awt.Component.dispatchEvent(Component.java:4460)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
        at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:117)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)