java.lang.IllegalStateException: Container org.netbeans.core.windows.frames.SplitContainerImpl[,0,0,313x878,layout=java.awt.BorderLayout,alignmentX=null,alignmentY=null,border=javax.swing.border.EmptyBorder@5c0102,flags=9,maximumSize=,minimumSize=,preferredSize=] has not drop target glass pane -> org.openide.explorer.view.DropGlassPane[,0,0,313x878,layout=java.awt.FlowLayout,alignmentX=null,alignmentY=null,border=,flags=1,maximumSize=,minimumSize=,preferredSize=]
        at org.netbeans.core.windows.frames.DefaultContainerImpl.windowDragStarting(DefaultContainerImpl.java:397)
        at org.netbeans.core.windows.dnd.WindowDnDManager.dragStarting(WindowDnDManager.java:170)
        at org.netbeans.core.windows.dnd.TopComponentDragSupport.doStartDrag(TopComponentDragSupport.java:351)
        at org.netbeans.core.windows.dnd.TopComponentDragSupport.eventDispatched(TopComponentDragSupport.java:274)
        at java.awt.Toolkit$SelectiveAWTEventListener.eventDispatched(Toolkit.java:2114)
        at java.awt.Toolkit$ToolkitEventMulticaster.eventDispatched(Toolkit.java:2008)
        at java.awt.Toolkit$ToolkitEventMulticaster.eventDispatched(Toolkit.java:2007)
        at java.awt.Toolkit$ToolkitEventMulticaster.eventDispatched(Toolkit.java:2007)
        at java.awt.Toolkit$ToolkitEventMulticaster.eventDispatched(Toolkit.java:2007)
        at java.awt.Toolkit$ToolkitEventMulticaster.eventDispatched(Toolkit.java:2007)
        at java.awt.Toolkit$ToolkitEventMulticaster.eventDispatched(Toolkit.java:2007)
        at java.awt.Toolkit$ToolkitEventMulticaster.eventDispatched(Toolkit.java:2007)
        at java.awt.Toolkit$ToolkitEventMulticaster.eventDispatched(Toolkit.java:2007)
        at java.awt.Toolkit$ToolkitEventMulticaster.eventDispatched(Toolkit.java:2007)
        at java.awt.Toolkit.notifyAWTEventListeners(Toolkit.java:1966)
        at java.awt.Component.dispatchEventImpl(Component.java:3441)
        at java.awt.Container.dispatchEventImpl(Container.java:1437)
        at java.awt.Component.dispatchEvent(Component.java:3367)
        at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:3214)
        at java.awt.LightweightDispatcher.processMouseEvent(Container.java:2946)
        at java.awt.LightweightDispatcher.dispatchEvent(Container.java:2859)
        at java.awt.Container.dispatchEventImpl(Container.java:1423)
        at java.awt.Window.dispatchEventImpl(Window.java:1566)
        at java.awt.Component.dispatchEvent(Component.java:3367)
[catch] at java.awt.EventQueue.dispatchEvent(EventQueue.java:445)
        at java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:190)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:144)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:138)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:130)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:98)