Renaming Sheets with Calculate

[JonTuxIvy]

Not a code man, just trying to find some help

1. I have a worksheet named "Margin" where a user enters several names in cells B11 through B24 for different projects.
2. The following worksheets have a cell (A4:E4 Merged) that calculates its name from the appropriate cell in "Margin".
   (=Margin!B11 for example)
3. I would then like to have each worksheet name itself based on that value
4. If a relevant value is blank (ie no project name), the worksheet should hide itself.

This is my code (borrowed from several sources) but it is not functioning. Help would be appreciated.

• Possible issues... IsEmpty is not the correct command since the fomula returns "0" for a blank cell?
• The macro does not seem to be running at all...even just a name change is not renaming the tab?

Thanks for any pointers you have!

 Private Sub Worksheet_calculate()
   Dim Target As Range
   Set Target = Me.Range("A4")
    
    'If the target cell is empty (contents cleared) then do not change the sheet name and hide worksheet
   If IsEmpty(Target) Then Me.Visible = xlSheetVeryHidden
   Exit Sub
     
    'If the length of the target cell's entry is greater than 31 characters, disallow the entry.
   If Len(Target.Value) > 31 Then
        MsgBox "Worksheet tab names cannot be greater than 31 characters in length." & vbCrLf & _
        "You entered " & Target.Value & ", which has " & Len(Target.Value) & " characters.", , "Keep it under 31 characters"
        Application.EnableEvents = False
        Target.ClearContents
        Application.EnableEvents = True
        Exit Sub
    End If
    
    'Sheet tab names cannot contain the characters /, \, [, ], *, ?, or :.
    'Verify that none of these characters are present in the cell's entry.
   Dim IllegalCharacter(1 To 7) As String, i As Integer
    IllegalCharacter(1) = "/"
    IllegalCharacter(2) = "\"
    IllegalCharacter(3) = "["
    IllegalCharacter(4) = "]"
    IllegalCharacter(5) = "*"
    IllegalCharacter(6) = "?"
    IllegalCharacter(7) = ":"
    For i = 1 To 7
        If InStr(Target.Value, (IllegalCharacter(i))) > 0 Then
            MsgBox "You used a character that violates sheet naming rules." & vbCrLf & vbCrLf & _
            "Please re-enter a name without the ''" & IllegalCharacter(i) & "'' character.", 48, "Not a possible sheet name !!"
            Application.EnableEvents = False
            Target.ClearContents
            Application.EnableEvents = True
            Exit Sub
        End If
    Next i

    'Verify that the proposed sheet name does not already exist in the workbook.
   Dim strSheetName As String, wks As Worksheet, bln As Boolean
    strSheetName = Trim(Target.Value)
    On Error Resume Next
    Set wks = ActiveWorkbook.Worksheets(strSheetName)
    On Error Resume Next
    If Not wks Is Nothing Then
        bln = True
    Else
        bln = False
        Err.Clear
    End If

    'If the worksheet name does not already exist, name the active sheet as the target cell value.
   'Otherwise, advise the user that duplicate sheet names are not allowed.
   If bln = False Then
        Me.Name = Target.Value
    Else
        MsgBox "There is already a sheet named " & strSheetName & "." & vbCrLf & _
        "Please enter a unique name for the system."
        Application.EnableEvents = False
        Target.ClearContents
        Application.EnableEvents = True
    End If
End Sub

Added code tags...sorry about that