java.lang.NullPointerException
        at org.netbeans.modules.form.layoutdesign.LayoutModel.removeInterval(LayoutModel.java:301)
        at org.netbeans.modules.form.layoutdesign.LayoutDesigner.intervalRemoved(LayoutDesigner.java:3736)
        at org.netbeans.modules.form.layoutdesign.LayoutDesigner.layoutChanged(LayoutDesigner.java:2184)
        at org.netbeans.modules.form.layoutdesign.LayoutDesigner.access$100(LayoutDesigner.java:35)
        at org.netbeans.modules.form.layoutdesign.LayoutDesigner$Listener.layoutChanged(LayoutDesigner.java:2150)
        at org.netbeans.modules.form.layoutdesign.LayoutModel.fireEvent(LayoutModel.java:772)
        at org.netbeans.modules.form.layoutdesign.LayoutModel.removeInterval(LayoutModel.java:307)
        at org.netbeans.modules.form.layoutdesign.LayoutModel.removeComponentAndIntervals(LayoutModel.java:254)
        at org.netbeans.modules.form.layoutdesign.LayoutDesigner.addComponents(LayoutDesigner.java:747)
        at org.netbeans.modules.form.layoutdesign.LayoutDesigner.endMoving(LayoutDesigner.java:703)
        at org.netbeans.modules.form.HandleLayer$ResizeComponentDrag.end(HandleLayer.java:2491)
        at org.netbeans.modules.form.HandleLayer$ComponentDrag.end(HandleLayer.java:2133)
        at org.netbeans.modules.form.HandleLayer.endDragging(HandleLayer.java:928)
        at org.netbeans.modules.form.HandleLayer.mouseReleased(HandleLayer.java:1483)
        at java.awt.Component.processMouseEvent(Component.java:6038)
        at javax.swing.JComponent.processMouseEvent(JComponent.java:3260)
        at java.awt.Component.processEvent(Component.java:5803)
        at java.awt.Container.processEvent(Container.java:2058)
        at java.awt.Component.dispatchEventImpl(Component.java:4410)
        at java.awt.Container.dispatchEventImpl(Container.java:2116)
        at java.awt.Component.dispatchEvent(Component.java:4240)
        at java.awt.LightweightDispatcher.retargetMouseEvent(LightweightDispatcher.java:4322)
        at java.awt.LightweightDispatcher.processMouseEvent(LightweightDispatcher.java:3986)
        at java.awt.LightweightDispatcher.dispatchEvent(LightweightDispatcher.java:3916)
        at java.awt.Container.dispatchEventImpl(Container.java:2102)
        at java.awt.Window.dispatchEventImpl(Window.java:2429)
        at java.awt.Component.dispatchEvent(Component.java:4240)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:273)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:183)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:173)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:168)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:160)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:121)