Reproducible scenario (Windows 7 Enterprise,  32 bit):

1) Create a wpf application and put one xamMaskedEditor and one TextBox (don't have to put any logic in the project)

2) Create a user "testuser" and put it in the Users groups (not Administrator)

3) From an administrator account shift+right click the wpf application, run->as different user, enter "testuser" credentials

4) Perform a single left click in TextBox (this works, the click is performed)

5) Perform in the xamMaskedEditor

Expected Result: focusing the xamMaskedEditor (i.e. the caret is put in the xamTextEditor)

Actual Result: application crashes with the exception:

Application: WpfApplication1.exe

Framework Version: v4.0.30319
Description: The process was terminated due to an unhandled exception.
Exception Info: System.Runtime.InteropServices.COMException
Stack:
   at MS.Win32.UnsafeNativeMethods+ITfThreadMgr.GetGlobalCompartment(ITfCompartmentMgr ByRef)
   at System.Windows.Input.TextServicesCompartmentContext.GetGlobalCompartment(System.Guid)
   at System.Windows.Input.InputMethod.InitializeCompartmentEventSink()
   at System.Windows.Input.InputMethod.add_StateChanged(System.Windows.Input.InputMethodStateChangedEventHandler)
   at Infragistics.Windows.Editors.EditInfo+TextBoxEventProxy.WireInputMethod_StateChanged()
   at Infragistics.Windows.Editors.EditInfo.HookUnhookInputMethodHelper(Boolean)
   at Infragistics.Windows.Editors.XamMaskedEditor.ProcessIsBeingEditedAndFocusedChanged(Boolean)
   at Infragistics.Windows.Editors.XamMaskedEditor.ProcessIsBeingEditedAndFocusedChanged()
   at Infragistics.Windows.Editors.XamMaskedEditor.OnEditModeStarted(Infragistics.Windows.Editors.Events.EditModeStartedEventArgs)
   at Infragistics.Windows.Editors.ValueEditor.RaiseEditModeStarted(Infragistics.Windows.Editors.Events.EditModeStartedEventArgs)
   at Infragistics.Windows.Editors.ValueEditor.StartEditMode(Boolean)
   at Infragistics.Windows.Editors.ValueEditor.OnIsFocusWithinChanged(Boolean)
   at Infragistics.Windows.Editors.ValueEditor.OnPropertyChanged(System.Windows.DependencyPropertyChangedEventArgs)
   at Infragistics.Windows.Editors.TextEditorBase.OnPropertyChanged(System.Windows.DependencyPropertyChangedEventArgs)
   at Infragistics.Windows.Editors.XamMaskedEditor.OnPropertyChanged(System.Windows.DependencyPropertyChangedEventArgs)
   at System.Windows.DependencyObject.NotifyPropertyChange(System.Windows.DependencyPropertyChangedEventArgs)
   at System.Windows.DependencyObject.UpdateEffectiveValue(System.Windows.EntryIndex, System.Windows.DependencyProperty, System.Windows.PropertyMetadata, System.Windows.EffectiveValueEntry, System.Windows.EffectiveValueEntry ByRef, Boolean, Boolean, System.Windows.OperationType)
   at System.Windows.DependencyObject.SetValueCommon(System.Windows.DependencyProperty, System.Object, System.Windows.PropertyMetadata, Boolean, Boolean, System.Windows.OperationType, Boolean)
   at System.Windows.DependencyObject.SetValue(System.Windows.DependencyPropertyKey, System.Object)
   at Infragistics.Windows.Helpers.FocusWithinManager.SetFocusWithin(System.Windows.DependencyObject, Boolean, System.Windows.DependencyObject)
   at Infragistics.Windows.Helpers.FocusWithinManager.VerifyFocusWithin(System.Windows.DependencyObject, Boolean)
   at Infragistics.Windows.Helpers.FocusWithinManager.OnGotFocusClassHandler(System.Object, System.Windows.RoutedEventArgs)
   at System.Windows.RoutedEventHandlerInfo.InvokeHandler(System.Object, System.Windows.RoutedEventArgs)
   at System.Windows.EventRoute.InvokeHandlersImpl(System.Object, System.Windows.RoutedEventArgs, Boolean)
   at System.Windows.UIElement.RaiseEventImpl(System.Windows.DependencyObject, System.Windows.RoutedEventArgs)
   at System.Windows.UIElement.RaiseEvent(System.Windows.RoutedEventArgs)
   at System.Windows.FrameworkElement.OnGotFocus(System.Windows.RoutedEventArgs)
   at System.Windows.UIElement.IsFocused_Changed(System.Windows.DependencyObject, System.Windows.DependencyPropertyChangedEventArgs)
   at System.Windows.DependencyObject.OnPropertyChanged(System.Windows.DependencyPropertyChangedEventArgs)
   at System.Windows.FrameworkElement.OnPropertyChanged(System.Windows.DependencyPropertyChangedEventArgs)
   at Infragistics.Windows.Editors.ValueEditor.OnPropertyChanged(System.Windows.DependencyPropertyChangedEventArgs)
   at Infragistics.Windows.Editors.TextEditorBase.OnPropertyChanged(System.Windows.DependencyPropertyChangedEventArgs)
   at Infragistics.Windows.Editors.XamMaskedEditor.OnPropertyChanged(System.Windows.DependencyPropertyChangedEventArgs)
   at System.Windows.DependencyObject.NotifyPropertyChange(System.Windows.DependencyPropertyChangedEventArgs)
   at System.Windows.DependencyObject.UpdateEffectiveValue(System.Windows.EntryIndex, System.Windows.DependencyProperty, System.Windows.PropertyMetadata, System.Windows.EffectiveValueEntry, System.Windows.EffectiveValueEntry ByRef, Boolean, Boolean, System.Windows.OperationType)
   at System.Windows.DependencyObject.SetValueCommon(System.Windows.DependencyProperty, System.Object, System.Windows.PropertyMetadata, Boolean, Boolean, System.Windows.OperationType, Boolean)
   at System.Windows.DependencyObject.SetValue(System.Windows.DependencyPropertyKey, System.Object)
   at System.Windows.Input.FocusManager.OnFocusedElementChanged(System.Windows.DependencyObject, System.Windows.DependencyPropertyChangedEventArgs)
   at System.Windows.DependencyObject.OnPropertyChanged(System.Windows.DependencyPropertyChangedEventArgs)
   at System.Windows.FrameworkElement.OnPropertyChanged(System.Windows.DependencyPropertyChangedEventArgs)
   at System.Windows.DependencyObject.NotifyPropertyChange(System.Windows.DependencyPropertyChangedEventArgs)
   at System.Windows.DependencyObject.UpdateEffectiveValue(System.Windows.EntryIndex, System.Windows.DependencyProperty, System.Windows.PropertyMetadata, System.Windows.EffectiveValueEntry, System.Windows.EffectiveValueEntry ByRef, Boolean, Boolean, System.Windows.OperationType)
   at System.Windows.DependencyObject.SetValueCommon(System.Windows.DependencyProperty, System.Object, System.Windows.PropertyMetadata, Boolean, Boolean, System.Windows.OperationType, Boolean)
   at System.Windows.DependencyObject.SetValue(System.Windows.DependencyProperty, System.Object)
   at System.Windows.Input.FocusManager.SetFocusedElement(System.Windows.DependencyObject, System.Windows.IInputElement)
   at System.Windows.Input.KeyboardNavigation.UpdateFocusedElement(System.Windows.DependencyObject)
   at System.Windows.FrameworkElement.OnGotKeyboardFocus(System.Object, System.Windows.Input.KeyboardFocusChangedEventArgs)
   at System.Windows.Input.KeyboardFocusChangedEventArgs.InvokeEventHandler(System.Delegate, System.Object)
   at System.Windows.RoutedEventArgs.InvokeHandler(System.Delegate, System.Object)
   at System.Windows.RoutedEventHandlerInfo.InvokeHandler(System.Object, System.Windows.RoutedEventArgs)
   at System.Windows.EventRoute.InvokeHandlersImpl(System.Object, System.Windows.RoutedEventArgs, Boolean)
   at System.Windows.UIElement.RaiseEventImpl(System.Windows.DependencyObject, System.Windows.RoutedEventArgs)
   at System.Windows.UIElement.RaiseTrustedEvent(System.Windows.RoutedEventArgs)
   at System.Windows.UIElement.RaiseEvent(System.Windows.RoutedEventArgs, Boolean)
   at System.Windows.Input.InputManager.ProcessStagingArea()
   at System.Windows.Input.InputManager.ProcessInput(System.Windows.Input.InputEventArgs)
   at System.Windows.Input.KeyboardDevice.ChangeFocus(System.Windows.DependencyObject, Int32)
   at System.Windows.Input.KeyboardDevice.TryChangeFocus(System.Windows.DependencyObject, System.Windows.Input.IKeyboardInputProvider, Boolean, Boolean, Boolean)
   at System.Windows.Input.KeyboardDevice.Focus(System.Windows.DependencyObject, Boolean, Boolean, Boolean)
   at System.Windows.Input.KeyboardDevice.Focus(System.Windows.IInputElement)
   at System.Windows.UIElement.Focus()
   at Infragistics.Windows.Editors.ValueEditor.StartEditModeOnMouseDownHelper()
   at Infragistics.Windows.Editors.ValueEditor.OnMouseLeftButtonDown(System.Windows.Input.MouseButtonEventArgs)
   at Infragistics.Windows.Editors.TextEditorBase.OnMouseLeftButtonDown(System.Windows.Input.MouseButtonEventArgs)
   at Infragistics.Windows.Editors.XamMaskedEditor.OnMouseLeftButtonDown(System.Windows.Input.MouseButtonEventArgs)
   at System.Windows.UIElement.OnMouseLeftButtonDownThunk(System.Object, System.Windows.Input.MouseButtonEventArgs)
   at System.Windows.Input.MouseButtonEventArgs.InvokeEventHandler(System.Delegate, System.Object)
   at System.Windows.RoutedEventArgs.InvokeHandler(System.Delegate, System.Object)
   at System.Windows.RoutedEventHandlerInfo.InvokeHandler(System.Object, System.Windows.RoutedEventArgs)
   at System.Windows.EventRoute.InvokeHandlersImpl(System.Object, System.Windows.RoutedEventArgs, Boolean)
   at System.Windows.UIElement.ReRaiseEventAs(System.Windows.DependencyObject, System.Windows.RoutedEventArgs, System.Windows.RoutedEvent)
   at System.Windows.UIElement.OnMouseDownThunk(System.Object, System.Windows.Input.MouseButtonEventArgs)
   at System.Windows.Input.MouseButtonEventArgs.InvokeEventHandler(System.Delegate, System.Object)
   at System.Windows.RoutedEventArgs.InvokeHandler(System.Delegate, System.Object)
   at System.Windows.RoutedEventHandlerInfo.InvokeHandler(System.Object, System.Windows.RoutedEventArgs)
   at System.Windows.EventRoute.InvokeHandlersImpl(System.Object, System.Windows.RoutedEventArgs, Boolean)
   at System.Windows.UIElement.RaiseEventImpl(System.Windows.DependencyObject, System.Windows.RoutedEventArgs)
   at System.Windows.UIElement.RaiseTrustedEvent(System.Windows.RoutedEventArgs)
   at System.Windows.UIElement.RaiseEvent(System.Windows.RoutedEventArgs, Boolean)
   at System.Windows.Input.InputManager.ProcessStagingArea()
   at System.Windows.Input.InputManager.ProcessInput(System.Windows.Input.InputEventArgs)
   at System.Windows.Input.InputProviderSite.ReportInput(System.Windows.Input.InputReport)
   at System.Windows.Interop.HwndMouseInputProvider.ReportInput(IntPtr, System.Windows.Input.InputMode, Int32, System.Windows.Input.RawMouseActions, Int32, Int32, Int32)
   at System.Windows.Interop.HwndMouseInputProvider.FilterMessage(IntPtr, MS.Internal.Interop.WindowMessage, IntPtr, IntPtr, Boolean ByRef)
   at System.Windows.Interop.HwndSource.InputFilterMessage(IntPtr, Int32, IntPtr, IntPtr, Boolean ByRef)
   at MS.Win32.HwndWrapper.WndProc(IntPtr, Int32, IntPtr, IntPtr, Boolean ByRef)
   at MS.Win32.HwndSubclass.DispatcherCallbackOperation(System.Object)
   at System.Windows.Threading.ExceptionWrapper.InternalRealCall(System.Delegate, System.Object, Int32)
   at MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(System.Object, System.Delegate, System.Object, Int32, System.Delegate)
   at System.Windows.Threading.Dispatcher.InvokeImpl(System.Windows.Threading.DispatcherPriority, System.TimeSpan, System.Delegate, System.Object, Int32)
   at MS.Win32.HwndSubclass.SubclassWndProc(IntPtr, Int32, IntPtr, IntPtr)
   at MS.Win32.UnsafeNativeMethods.DispatchMessage(System.Windows.Interop.MSG ByRef)
   at System.Windows.Threading.Dispatcher.PushFrameImpl(System.Windows.Threading.DispatcherFrame)
   at System.Windows.Threading.Dispatcher.PushFrame(System.Windows.Threading.DispatcherFrame)
   at System.Windows.Threading.Dispatcher.Run()
   at System.Windows.Application.RunDispatcher(System.Object)
   at System.Windows.Application.RunInternal(System.Windows.Window)
   at System.Windows.Application.Run(System.Windows.Window)
   at System.Windows.Application.Run()
   at WpfApplication1.App.Main()

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Additional details:

I've reproduced it on multiple windows 7 Enterprise machines both x64 and x32.

The error doesn't reproduce if I do an interactive login with "tableuser" instead of doing a ***+right click, run->as login

The error doesn't reproduce if I do a shift+right click, run as "tableuser" and I have "tableuser" in the administrator group instead of normal users group, and in addition to that, have UAC disabled.

In all other cases the error reproduces.