Aufgabe Fehlermeldung nachdem die Programm-Einstellungen geschlossen wurden

Beim Speichern / Schließen des Fensters mit den Programm-Einstellungen tritt folgende Fehlermeldung auf:

java.lang.NullPointerException
at com.openindex.openestate.tool.ImmoToolSetupDialog$2.valueChanged(ImmoToolSetupDialog.java:113):629)
at javax.swing.tree.DefaultTreeSelectionModel.clearSelection(DefaultTreeSelectionModel.java:570):2136)
at com.openindex.openestate.tool.ImmoToolUtils.dispose(ImmoToolUtils.java:1028):1154)
at com.openindex.openestate.tool.ImmoToolUtils.disposeRecursively(ImmoToolUtils.java:1135):1135)
at com.openindex.openestate.tool.ImmoToolUtils.disposeRecursively(ImmoToolUtils.java:1135):1135)
at com.openindex.openestate.tool.ImmoToolUtils.disposeRecursively(ImmoToolUtils.java:1135):1135)
at com.openindex.openestate.tool.ImmoToolUtils.disposeRecursively(ImmoToolUtils.java:1135):209)
at com.openindex.openestate.tool.ImmoToolView.doShowSetupDialog(ImmoToolView.java:2073):39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25):592)
at org.jdesktop.application.ApplicationAction.noProxyActionPerformed(ApplicationAction.java:662):698)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1849):2169)
at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:420):258)
at javax.swing.AbstractButton.doClick(AbstractButton.java:302):1050)
at javax.swing.plaf.basic.BasicMenuItemUI$Handler.mouseReleased(BasicMenuItemUI.java:1091):231)
at java.awt.Component.processMouseEvent(Component.java:5517):3129)
at java.awt.Component.processEvent(Component.java:5282):1966)
at java.awt.Component.dispatchEventImpl(Component.java:3984):2024)
at java.awt.Component.dispatchEvent(Component.java:3819):4212)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:3892):3822)
at java.awt.Container.dispatchEventImpl(Container.java:2010):1791)
at java.awt.Component.dispatchEvent(Component.java:3819):463)
at java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:242):163)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:157):149)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:110)

Die Speicherung der Einstellungen wird trotz der Fehlermeldung durchgeführt.