I have a column of cells with text which I want to sort alphabetically. But not all cells should be sorted by their first characters. In these cells the character by which they should be sorted is formatted with a (single) underline.
Now I want to create an auxiliary column which contains only

• for strings that have at least one char underlined: the (rest of the) string, starting with the underlined character
• for strings without underlined char: the full string

Example columns

I got some VBA code together which looks reasonable to me (with help from ChatGPT:-):

Function GetUnderlinedText(inputText As String) As String
    Dim cell As Range
    Dim underlinedCharIndex As Long
    Dim underlinedText As String

    ' Get the reference to the cell
    Set cell = Application.Caller

    ' Find the index of the first underlined character
    underlinedCharIndex = FindUnderlinedChar(inputText)

    ' If underlined character found, return the portion of text starting from that character
    If underlinedCharIndex > 0 Then
        underlinedText = Mid(inputText, underlinedCharIndex)
    Else
        underlinedText = inputText
    End If

    ' Return the underlined portion of the text
    GetUnderlinedText = underlinedText
End Function

Function FindUnderlinedChar(inputText As String) As Long
    Dim i As Long
    Dim char As String

    ' Iterate through each character of the text
    For i = 1 To Len(inputText)
        char = Mid(inputText, i, 1)
        ' Check if the character is underlined
        If IsUnderlined(inputText, i) Then
            ' Return the index of the underlined character
            FindUnderlinedChar = i
            Exit Function
        End If
    Next i

    ' If no underlined character found, return 0
    FindUnderlinedChar = 0
End Function

Function IsUnderlined(inputText As String, position As Long) As Boolean
    ' Check if the character at the specified position is underlined
    If Range("A1").Characters(position, 1).Font.Underline = xlUnderlineStyleSingle Then
        IsUnderlined = True
    Else
        IsUnderlined = False
    End If
End Function

Where I am stuck now is the Function IsUnderlined, which always returns TRUE.
In the debugger I can verify that Range("A1").Characters(position, 1).Font.Underlinenever changes its value of -4142 (= xlUnderlineStyleNone), even as I iterate through the characters.
Can anyone help what is wrong here?