Clone Assertions throws exception

Here is the error log:

ERROR: java.lang.NullPointerException
java.lang.NullPointerException
at com.eviware.soapui.impl.wsdl.actions.teststeps.testrequest.CloneAssertionsAction$3.valueChanged(CloneAssertionsAction.java:142)
at com.eviware.x.form.AbstractXFormField.fireValueChanged(AbstractXFormField.java:112)
at com.eviware.x.impl.swing.JBaseComboBoxFormField.itemStateChanged(JBaseComboBoxFormField.java:50)
at java.desktop/javax.swing.JComboBox.fireItemStateChanged(JComboBox.java:1227)
at java.desktop/javax.swing.JComboBox.selectedItemChanged(JComboBox.java:1279)
at java.desktop/javax.swing.JComboBox.contentsChanged(JComboBox.java:1335)
at java.desktop/javax.swing.AbstractListModel.fireContentsChanged(AbstractListModel.java:123)
at java.desktop/javax.swing.DefaultComboBoxModel.setSelectedItem(DefaultComboBoxModel.java:94)
at java.desktop/javax.swing.JComboBox.setSelectedItem(JComboBox.java:579)
at com.eviware.x.impl.swing.JBaseComboBoxFormField.setValue(JBaseComboBoxFormField.java:32)
at com.eviware.x.impl.swing.SwingXFormImpl.setComponentValue(SwingXFormImpl.java:274)
at com.eviware.x.impl.swing.JFormDialog.setValue(JFormDialog.java:192)
at com.eviware.soapui.impl.wsdl.actions.teststeps.testrequest.CloneAssertionsAction.perform(CloneAssertionsAction.java:163)
at com.eviware.soapui.impl.wsdl.actions.teststeps.testrequest.CloneAssertionsAction.perform(CloneAssertionsAction.java:1)
at com.eviware.soapui.support.action.swing.SwingActionDelegate.actionPerformed(SwingActionDelegate.java:176)
at java.desktop/javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1967)
at java.desktop/javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2308)
at java.desktop/javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:405)
at java.desktop/javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:262)
at java.desktop/javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:279)
at java.desktop/java.awt.AWTEventMulticaster.mouseReleased(AWTEventMulticaster.java:297)
at java.desktop/java.awt.Component.processMouseEvent(Component.java:6632)
at java.desktop/javax.swing.JComponent.processMouseEvent(JComponent.java:3342)
at java.desktop/java.awt.Component.processEvent(Component.java:6397)
at java.desktop/java.awt.Container.processEvent(Container.java:2263)
at java.desktop/java.awt.Component.dispatchEventImpl(Component.java:5008)
at java.desktop/java.awt.Container.dispatchEventImpl(Container.java:2321)
at java.desktop/java.awt.Component.dispatchEvent(Component.java:4840)
at java.desktop/java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4918)
at java.desktop/java.awt.LightweightDispatcher.processMouseEvent(Container.java:4547)
at java.desktop/java.awt.LightweightDispatcher.dispatchEvent(Container.java:4488)
at java.desktop/java.awt.Container.dispatchEventImpl(Container.java:2307)
at java.desktop/java.awt.Window.dispatchEventImpl(Window.java:2762)
at java.desktop/java.awt.Component.dispatchEvent(Component.java:4840)
at java.desktop/java.awt.EventQueue.dispatchEventImpl(EventQueue.java:772)
at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:721)
at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:715)
at java.base/java.security.AccessController.doPrivileged(AccessController.java:389)
at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:85)
at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:95)
at java.desktop/java.awt.EventQueue$5.run(EventQueue.java:745)
at java.desktop/java.awt.EventQueue$5.run(EventQueue.java:743)
at java.base/java.security.AccessController.doPrivileged(AccessController.java:389)
at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:85)
at java.desktop/java.awt.EventQueue.dispatchEvent(EventQueue.java:742)
at java.desktop/java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:203)
at java.desktop/java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:124)
at java.desktop/java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:113)
at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:109)
at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
at java.desktop/java.awt.EventDispatchThread.run(EventDispatchThread.java:90)