java.lang.ClassCastException: javax.swing.GroupLayout$ParallelGroup cannot be cast to javax.swing.GroupLayout$SequentialGroup
   at org.netbeans.modules.form.layoutdesign.support.SwingLayoutBuilder.fillGroup(SwingLayoutBuilder.java:313)
   at org.netbeans.modules.form.layoutdesign.support.SwingLayoutBuilder.composeGroup(SwingLayoutBuilder.java:242)
   at org.netbeans.modules.form.layoutdesign.support.SwingLayoutBuilder.fillGroup(SwingLayoutBuilder.java:270)
   at org.netbeans.modules.form.layoutdesign.support.SwingLayoutBuilder.composeGroup(SwingLayoutBuilder.java:242)
   at org.netbeans.modules.form.layoutdesign.support.SwingLayoutBuilder.fillGroup(SwingLayoutBuilder.java:261)
   at org.netbeans.modules.form.layoutdesign.support.SwingLayoutBuilder.composeGroup(SwingLayoutBuilder.java:242)
   at org.netbeans.modules.form.layoutdesign.support.SwingLayoutBuilder.fillGroup(SwingLayoutBuilder.java:270)
   at org.netbeans.modules.form.layoutdesign.support.SwingLayoutBuilder.composeGroup(SwingLayoutBuilder.java:242)
   at org.netbeans.modules.form.layoutdesign.support.SwingLayoutBuilder.createLayout(SwingLayoutBuilder.java:179)
   at org.netbeans.modules.form.layoutdesign.support.SwingLayoutBuilder.setupContainerLayout(SwingLayoutBuilder.java:108)
   at org.netbeans.modules.form.VisualReplicator.setupContainerLayout(VisualReplicator.java:900)
   at org.netbeans.modules.form.VisualReplicator.updateContainerLayout(VisualReplicator.java:366)
   at org.netbeans.modules.form.FormDesigner$LayoutMapper.rebuildLayout(FormDesigner.java:2306)
   at org.netbeans.modules.form.layoutdesign.LayoutDesigner.rebuildLayoutRecursively(LayoutDesigner.java:234)
   at org.netbeans.modules.form.layoutdesign.LayoutDesigner.updateCurrentState(LayoutDesigner.java:213)
   at org.netbeans.modules.form.FormDesigner.updateComponentLayer(FormDesigner.java:641)
   at org.netbeans.modules.form.FormDesigner.access$2200(FormDesigner.java:103)
   at org.netbeans.modules.form.FormDesigner$FormListener.run(FormDesigner.java:2701)
   at org.netbeans.modules.form.FormDesigner$FormListener.processEvents(FormDesigner.java:2545)
   at org.netbeans.modules.form.FormDesigner$FormListener.formChanged(FormDesigner.java:2504)
   at org.netbeans.modules.form.FormModel.fireEvents(FormModel.java:1327)
   at org.netbeans.modules.form.FormModel.fireEventBatch(FormModel.java:1300)
   at org.netbeans.modules.form.FormModel.firePendingEvents(FormModel.java:1263)
   at org.netbeans.modules.form.FormModel.access$000(FormModel.java:68)
   at org.netbeans.modules.form.FormModel$2.run(FormModel.java:1240)
   at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:311)
   at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:756)
   at java.awt.EventQueue.access$500(EventQueue.java:97)
   at java.awt.EventQueue$3.run(EventQueue.java:709)
   at java.awt.EventQueue$3.run(EventQueue.java:703)
   at java.security.AccessController.doPrivileged(AccessController.java:0)
   at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75)
   at java.awt.EventQueue.dispatchEvent(EventQueue.java:726)
   at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:159)
   at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
   at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
   at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
   at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
   at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
   at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)