Test if there is an open workbook with certain name

The function below if there is an open workbook with certain name. If it returns true this need not be the same file. It could be a file with the same name in a different folder. To determine if this is the case use wb.FullName.

Function IsOpenWorkbook(strWorkbookName As String, Optional bFullname As Boolean = False) As Boolean
'Purpose: check if there is already a file open with the same name
'Note: this function works correctly independent of Windows 'Show Extension' View setting
'debug.Print isOpenWorkbook(thisworkbook.Name)          = True '"MySavedFile.xls" - saved file
'debug.Print isOpenWorkbook(thisworkbook.Name,True)     = False '"MySavedFile.xls" - saved file
'debug.Print isOpenWorkbook(thisworkbook.FullName,False)= False '"..\MySavedFile.xls" - saved file
'debug.Print isOpenWorkbook(thisworkbook.FullName,True) = True '"..\MySavedFile.xls" - saved file
'debug.Print isOpenWorkbook("MySavedFile")              = False
'debug.Print isOpenWorkbook("book1")                    = True
'debug.Print isOpenWorkbook("book1.xls")                = False
Dim wb As Workbook
Dim strName As String
    IsOpenWorkbook = False
    For Each wb In Workbooks
        If bFullname = False Then
            strName = wb.Name
            strName = wb.FullName
        End If
        If (StrComp(strName, strWorkbookName, vbTextCompare) = 0) Then
            IsOpenWorkbook = True
            Exit Function
        End If
End Function