java.lang.NullPointerException
        at org.netbeans.modules.form.layoutdesign.LayoutModel.removeInterval(LayoutModel.java:334)
        at org.netbeans.modules.form.layoutdesign.LayoutDesigner.intervalRemoved(LayoutDesigner.java:3884)
        at org.netbeans.modules.form.layoutdesign.LayoutDesigner.layoutChanged(LayoutDesigner.java:2283)
        at org.netbeans.modules.form.layoutdesign.LayoutDesigner.access$100(LayoutDesigner.java:58)
        at org.netbeans.modules.form.layoutdesign.LayoutDesigner$Listener.layoutChanged(LayoutDesigner.java:2249)
        at org.netbeans.modules.form.layoutdesign.LayoutModel.fireEvent(LayoutModel.java:805)
        at org.netbeans.modules.form.layoutdesign.LayoutModel.removeInterval(LayoutModel.java:340)
        at org.netbeans.modules.form.layoutdesign.LayoutModel.removeComponentAndIntervals(LayoutModel.java:287)
        at org.netbeans.modules.form.layoutdesign.LayoutDesigner.addComponents(LayoutDesigner.java:811)
        at org.netbeans.modules.form.layoutdesign.LayoutDesigner.endMoving(LayoutDesigner.java:751)
        at org.netbeans.modules.form.HandleLayer$ExistingComponentDrag.end(HandleLayer.java:2687)
        at org.netbeans.modules.form.HandleLayer$ComponentDrag.end(HandleLayer.java:2463)
        at org.netbeans.modules.form.HandleLayer.endDragging(HandleLayer.java:1256)
        at org.netbeans.modules.form.HandleLayer.mouseReleased(HandleLayer.java:1812)
        at java.awt.Component.processMouseEvent(Component.java:6263)
        at javax.swing.JComponent.processMouseEvent(JComponent.java:3267)
        at java.awt.Component.processEvent(Component.java:6028)
        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:4238)
        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:104)
        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)