'''--------------------------------------------------------------------
''' <summary>
''' Retrieves the selection container for a selection item.
''' </summary>
''' <param name="selectionItem">
''' An automation element that supports SelectionItemPattern.
''' </param>
'''--------------------------------------------------------------------
Private Function GetSelectionItemContainer( _
ByVal selectionItem As AutomationElement) As AutomationElement
    ' Selection item cannot be null
    If selectionItem Is Nothing Then
        Throw New ArgumentException()
    End If

    Dim selectionItemPattern As SelectionItemPattern = _
    DirectCast(selectionItem.GetCurrentPattern( _
    selectionItemPattern.Pattern), SelectionItemPattern)
    If selectionItemPattern Is Nothing Then
        Return Nothing
    Else
        Return selectionItemPattern.Current.SelectionContainer
    End If
End Function 'GetSelectionItemContainer

'''--------------------------------------------------------------------
''' <summary>
''' Attempts to remove the current item from a collection 
''' of selected items. 
''' </summary>
''' <param name="selectionItem">
''' An automation element that supports SelectionItemPattern.
''' </param>
'''--------------------------------------------------------------------
Private Sub RemoveItemFromSelection( _
ByVal selectionItem As AutomationElement)
    If selectionItem Is Nothing Then
        Throw New ArgumentNullException( _
        "Argument cannot be null or empty.")
    End If

    Dim selectionContainer As AutomationElement = _
    GetSelectionItemContainer(selectionItem)

    ' Selection container cannot be null
    If selectionContainer Is Nothing Then
        Throw New ElementNotAvailableException()
    End If

    Dim selectionPattern As SelectionPattern = DirectCast( _
    selectionContainer.GetCurrentPattern(selectionPattern.Pattern), _
    SelectionPattern)

    If selectionPattern Is Nothing Then
        Return
    End If

    ' Check if a selection is required
    If selectionPattern.Current.IsSelectionRequired AndAlso _
    selectionPattern.Current.GetSelection().GetLength(0) <= 1 Then
        Return
    End If

    Dim selectionItemPattern As SelectionItemPattern = DirectCast( _
    selectionItem.GetCurrentPattern(selectionItemPattern.Pattern), _
    SelectionItemPattern)

    If Not (selectionItemPattern Is Nothing) AndAlso selectionItemPattern.Current.IsSelected Then
        Try
            selectionItemPattern.RemoveFromSelection()
        Catch
            ' Unable to remove from selection
            Return
        End Try
    End If
End Sub