Thank you for the detail description regarding the reported problem.

I try to summarize the problem and come up with the following resume.

• User opens up the second dialog box by clicking button on DialogBox1.
• After DialogBox2 appear, user selects an item from UXComboBox.
• MessagePresenter popup that says “Made it”, appear in the location as if the container is the DialogBox1 (which is not correct. It should be appearing on top of DialogBox2).

When a MessagePresenter is shown, the owner is defined by executing following line.

FrameworkElement element = ISFocusManager.GetFocusedElement() as FrameworkElement;
// check if the caller is hosted within a known container
// if the dependency container is of IWindow type, use it as the owner of this modal window
if (element != null)
{
    DependencyObject logicalContainer = ISFocusManager.GetLogicalContainerScope(element);
    if (logicalContainer is IWindow)
        _owner = logicalContainer as IWindow;
}

The owner is determined by getting the focused element. In the above scenario, the focused element after user selects an item from UXComboBox is the scroll viewer of UXComboBox’s result box. However, this element does no longer exist in the view – just after user selects an item, the result box of UXComboBox is collapsed.

It seems that when the focused element doesn’t exist in the view, GetLogicalContainerScope() method tries to look up from its parent. Please correct me if I’m wrong.

So I created a workaround for such behavior. In the MessageBoxServiceProvider class, I added a setter for Owner property so that the Owner property now looks like following snippet code.

public static IWindow Owner
{
    get
    {
        FrameworkElement element = ISFocusManager.GetFocusedElement() as FrameworkElement;
        // check if the caller is hosted within a known container
        // if the dependency container is of IWindow type, use it as the owner of this modal window
        if (element != null)
        {
            DependencyObject logicalContainer = ISFocusManager.GetLogicalContainerScope(element);
            if (logicalContainer is IWindow)
                _owner = logicalContainer as IWindow;
        }
        return _owner;
    }
    set { _owner = value; }
}

In DialogBox1EditViewModel class, I set the Owner property in AddAnotherDialogBox execute method as shown in the following snippet code.

public void AddAnotherDialogBox(object parameter)
{
    var vm = new DialogBox2EditViewModel();
    DialogBoxServiceProvider.GetInstanceAsync(
        DialogBoxServiceProvider.DialogBox2EditView,
        dialogBox =>
        {
            dialogBox.DataContext = vm;
            MessageBoxServiceProvider.Owner = dialogBox;
            DialogBoxServiceProvider.Show(dialogBox, null);
        });
}

By using this workaround, now the MessagePresenter popup on top of the UXDialogBox2.

I enclosed the modified project as attachment. Please feel free to let me know if you have different result or if I mistakenly understanding about the reported problem.

Thank you very much!!!! that works perfectly. Just another reason why Intersoft is the #1 .net controls provider. Not only is the product great and easy to use, the support is fantastic and fast.

Bill