XmlValueDisconnectedException when deleting a TestStep

Good Afternoon All,

We currently have 2 x Instances of SOAPUI Pro on 2 x identical machines. 1 works perfectly fine, whereas the 2nd PC is throwing the following exception when deleting a test step.

org.apache.xmlbeans.impl.values.XmlValueDisconnectedException
org.apache.xmlbeans.impl.values.XmlValueDisconnectedException
 at org.apache.xmlbeans.impl.values.XmlObjectBase.check_orphaned(XmlObjectBase.java:1244)
 at com.eviware.soapui.config.impl.TestCaseConfigImpl.sizeOfBreakPointsArray(Unknown Source)
 at com.eviware.soapui.config.impl.TestCaseConfigImpl$1BreakPointsList.size(Unknown Source)
 at java.util.AbstractList$Itr.hasNext(Unknown Source)
 at com.eviware.soapui.debug.BreakPoints.removeBreakPoint(SourceFile:185)
 at com.eviware.soapui.impl.wsdl.WsdlTestCasePro.removeTestStep(SourceFile:269)
 at com.eviware.soapui.impl.wsdl.actions.teststep.DeleteTestStepAction.perform(DeleteTestStepAction.java:45)
 at com.eviware.soapui.impl.wsdl.actions.teststep.DeleteTestStepAction.perform(DeleteTestStepAction.java:27)
 at com.eviware.soapui.support.action.swing.SwingActionDelegate.actionPerformed(SwingActionDelegate.java:89)
 at com.eviware.soapui.support.action.swing.DefaultActionList.dispatchKeyEvent(DefaultActionList.java:134)
 at com.eviware.soapui.ui.Navigator$TreeKeyListener.keyPressed(Navigator.java:238)
 at java.awt.AWTEventMulticaster.keyPressed(Unknown Source)
 at java.awt.Component.processKeyEvent(Unknown Source)
 at javax.swing.JComponent.processKeyEvent(Unknown Source)
 at java.awt.Component.processEvent(Unknown Source)
 at java.awt.Container.processEvent(Unknown Source)
 at java.awt.Component.dispatchEventImpl(Unknown Source)
 at java.awt.Container.dispatchEventImpl(Unknown Source)
 at java.awt.Component.dispatchEvent(Unknown Source)
 at java.awt.KeyboardFocusManager.redispatchEvent(Unknown Source)
 at java.awt.DefaultKeyboardFocusManager.dispatchKeyEvent(Unknown Source)
 at java.awt.DefaultKeyboardFocusManager.preDispatchKeyEvent(Unknown Source)
 at java.awt.DefaultKeyboardFocusManager.typeAheadAssertions(Unknown Source)
 at java.awt.DefaultKeyboardFocusManager.dispatchEvent(Unknown Source)
 at java.awt.Component.dispatchEventImpl(Unknown Source)
 at java.awt.Container.dispatchEventImpl(Unknown Source)
 at java.awt.Window.dispatchEventImpl(Unknown Source)
 at java.awt.Component.dispatchEvent(Unknown Source)
 at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
 at java.awt.EventQueue.access$200(Unknown Source)
 at java.awt.EventQueue$3.run(Unknown Source)
 at java.awt.EventQueue$3.run(Unknown Source)
 at java.security.AccessController.doPrivileged(Native Method)
 at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
 at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
 at java.awt.EventQueue$4.run(Unknown Source)
 at java.awt.EventQueue$4.run(Unknown Source)
 at java.security.AccessController.doPrivileged(Native Method)
 at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
 at java.awt.EventQueue.dispatchEvent(Unknown Source)
 at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
 at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
 at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
 at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
 at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
 at java.awt.EventDispatchThread.run(Unknown Source)

We have managed to get around the issue by running soapui as an 'Administrator', within the Shortcut settings - I have read on several forum pages that this has also occured in previous versions. Has anybody else come accross this in the latest version?

Using: SOAPUI Pro 4.6.4 with Composite Projects in SVN.