Troubleshoot "Unable to get the Buttons property of the Worksheet class"? - excel

Question

I created a 7-sheet Excel spreadsheet as a test-help companion to a popular bridge book by Kantar called "Modern Bridge Defense". The spreadsheet has a fairly large number of form buttons that allow a user to show or hide test answers from each of the seven chapters in the book
I have vba code that shows or hides the answer text, depending on the caption ('show' or 'hide') of the associated button, and a 'show/hide all' button that will show or hide all answers associated with a particular section of that chapter's test.
I also have vba code that initializes all the buttons on all 7 sheets. When the user first opens the spreadsheet, he/she is asked if they are OK with hiding all the answers. If they agree, the initialization routine loops through all 7 sheets, and the code for each sheet loops through all the buttons on that sheet, hiding each answer that isn't already hidden.
All this works fine if I step through the buttons in debug mode, but fails with "Unable to get the Buttons property of the Worksheet class" at some point (not always the same point) when I try to run it full speed.
This behavior seems like it might be some sort of timing/race issue, but I'm having trouble imagining how that could be, as I don't think I'm really tasking my laptop (XPS15 7590 with 32GB Ram, 1TB SSD).
Here is my initialization routine and the function it calls to iterate through the sheet buttons:
Option Explicit
Private Sub Workbook_Open()
Debug.Print ("In Workbook_Open()")
Dim res As VbMsgBoxResult
res = MsgBox("Hide all answers?", vbYesNoCancel, "Kantar Test Initialization")
If res = vbYes Then
res = MsgBox("Caution! This action will hide all answers - Are you SURE you want to do this?", vbYesNoCancel, "Are you SURE?")
If res = vbYes Then
'OK, user is sure about doing this!
Dim sheet As Worksheet
For Each sheet In Application.Sheets
Debug.Print "Initializing worksheet " & sheet.Name
On Error Resume Next
InitializeAllButtons sheet
If Err <> 0 Then
Debug.Print "call to InitializeAllButtons)" & sheet.Name & " failed with " & Err.Description
End If
Next sheet
End If
End If
End Sub
and here's the function that actually 'clicks' the buttons
Sub InitializeAllButtons(sheet As Worksheet)
Dim btn As Excel.Button, addrstr, startcellstr, startrowstr, endrowstr, colstr As String
Dim pos As Integer
Dim startrow As Integer
Dim endrow As Integer
Dim col As Integer
Dim rownum As Integer
With sheet
For Each btn In .Buttons
Debug.Print (vbTab & btn.Name & ", " & btn.Caption)
'11/27/22 rev to set 'all' button captions to 'Hide All', click on all 'Hide' row buttons
If InStr(btn.Caption, "All") > 0 Then
btn.Caption = "Show All"
Debug.Print "btn " & btn.Name & " caption changed to Show All"
Else 'is normal row show/hide button
If btn.Caption = "Hide" Then
RowButtonClick (btn.Name)
End If
End If
Next
End With
End Sub
In response to a question, here is the 'RowButtonClick()' function
Function RowButtonClick(btn_name As String) As Integer
Dim btn As Excel.Button
Dim btn_text As String
Dim cellstr As String
Dim row, col As Integer
Dim textrange As Range
'for multiple row show/hide ops
Dim cellstrlen As Integer
Dim startrowstr, endrowstr, startcolstr As String
Dim startrow As Integer
Dim endrow As Integer
Dim charidx As Integer
'11/24/22 multiple row button names include '_'
charidx = InStr(btn_name, "_")
If charidx > 0 Then
'11/24/22 row addresses may be 1, 2, or 3 digits
GetStartEndRowCol btn_name, startrow, endrow, col
Debug.Print ("RBC just after GSER: start row = " & startrow & ", end row = " & endrow)
Else 'single row: endrow = startrow
cellstr = Mid(btn_name, 9)
startrow = Range(cellstr).row
endrow = startrow
col = Range(cellstr).Column
Debug.Print "RBC: Single row show/hide action"
End If
Set btn = Application.ActiveSheet.Buttons(btn_name)
btn_text = btn.Caption
With Application.ActiveSheet
If btn_text = "Show" Then
Application.ActiveSheet.Range(.Cells(startrow, col + 1), .Cells(endrow, col + 2)).NumberFormat = ""
btn.Caption = "Hide"
Else
Application.ActiveSheet.Range(.Cells(startrow, col + 1), .Cells(endrow, col + 2)).NumberFormat = "; ; ;"
btn.Caption = "Show"
End If
End With
RowButtonClick = endrow 'so calling fcn knows the next row to try
End Function