[#5603] - When adding a field in a nested list and then pressing “ctrl-z” multiple times to undo the changes, it throws a Null Pointer

When adding a field in a nested list and then pressing “ctrl-z” multiple times to undo the changes, it throws a Null Pointer Exception

java.lang.NullPointerException
at com.jaspersoft.ireport.designer.undo.UndoMoveChildrenUndoableEdit.updateChildren(UndoMoveChildrenUndoableEdit.java:98)
at com.jaspersoft.ireport.designer.undo.UndoMoveChildrenUndoableEdit.updateChildren(UndoMoveChildrenUndoableEdit.java:83)
at com.jaspersoft.ireport.designer.undo.UndoMoveChildrenUndoableEdit.undo(UndoMoveChildrenUndoableEdit.java:51)
at com.jaspersoft.ireport.designer.undo.AggregatedUndoableEdit.undo(AggregatedUndoableEdit.java:60)
at javax.swing.undo.UndoManager.undoTo(UndoManager.java:320)
at javax.swing.undo.UndoManager.undo(UndoManager.java:398)
at com.jaspersoft.ireport.designer.undo.UndoRedoManager.superUndo(UndoRedoManager.java:54)
at com.jaspersoft.ireport.designer.undo.UndoRedoManager.undo(UndoRedoManager.java:63)
at org.netbeans.core.multiview.MultiViewPeer$DelegateUndoRedo.undo(MultiViewPeer.java:773)
at org.openide.actions.UndoAction.performAction(UndoAction.java:177)
at org.openide.util.actions.CallableSystemAction$1.run(CallableSystemAction.java:118)
at org.netbeans.modules.openide.util.ActionsBridge.doPerformAction(ActionsBridge.java:77)
at org.openide.util.actions.CallableSystemAction.actionPerformed(CallableSystemAction.java:114)
at org.openide.windows.TopComponent.processKeyBinding(TopComponent.java:1007)
at javax.swing.JComponent.processKeyBindings(JComponent.java:2897)
at javax.swing.JComponent.processKeyEvent(JComponent.java:2814)
at java.awt.Component.processEvent(Component.java:6065)
at java.awt.Container.processEvent(Container.java:2041)
at java.awt.Component.dispatchEventImpl(Component.java:4651)
at java.awt.Container.dispatchEventImpl(Container.java:2099)
at java.awt.Component.dispatchEvent(Component.java:4481)
at java.awt.KeyboardFocusManager.redispatchEvent(KeyboardFocusManager.java:1850)
at java.awt.DefaultKeyboardFocusManager.dispatchKeyEvent(DefaultKeyboardFocusManager.java:712)
at java.awt.DefaultKeyboardFocusManager.preDispatchKeyEvent(DefaultKeyboardFocusManager.java:990)
at java.awt.DefaultKeyboardFocusManager.typeAheadAssertions(DefaultKeyboardFocusManager.java:855)
at java.awt.DefaultKeyboardFocusManager.dispatchEvent(DefaultKeyboardFocusManager.java:676)
at java.awt.Component.dispatchEventImpl(Component.java:4523)
at java.awt.Container.dispatchEventImpl(Container.java:2099)
at java.awt.Window.dispatchEventImpl(Window.java:2478)
at java.awt.Component.dispatchEvent(Component.java:4481)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:643)
at java.awt.EventQueue.access$000(EventQueue.java:84)
at java.awt.EventQueue$1.run(EventQueue.java:602)
at java.awt.EventQueue$1.run(EventQueue.java:600)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)
at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:98)
at java.awt.EventQueue$2.run(EventQueue.java:616)
at java.awt.EventQueue$2.run(EventQueue.java:614)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)
[catch] at java.awt.EventQueue.dispatchEvent(EventQueue.java:613)
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)

After adding columns in nested list, I cannot delete or change the column location.