ComboBox and .Find

Warning: code will be infinite loop!

Hello, I have multiple comboboxes in a userform and I want the second combobox list to be dependent upon the first combobox. The first combobox simply goes through a spreadsheet and adds the cell values from the first column. I want the second combobox to add items that are next to the cell that matches the value of the selected item from the first combobox. I currently have

Private Sub ComboBox1_Change()

With Sheets("Schedule")
    idx = ComboBox1.ListIndex
    Set x = .Range("A:A").Find(what:=ComboBox2.Value, LookIn:=xlValues, lookat:=xlPart)
    If Not x Is Nothing Then
        firstAddress = x.Address
        Do
            ComboBox2.AddItem .Cells(x.Row, "B").Value
            
            Set x = .Range("A:A").FindNext(x)
        Loop While Not x Is Nothing And x.Address <> firstAddress
    End If
End With

End Sub

but this is not working. It is difficut to explain what I would like exactly, so I will upload the workbook as well, if needed.
Thanks in advance!

Wait, I am not sure if that would work... Could you elaborate?

Good Thinking. I also realized a simple, silly error in my code that fixes it anyways. Your idea is much simpler though.

Sure thing. It is on the OutgoingUF. And it uses the 'Schedule' WS.

Correct Document.xlsm

The way I have it now works correctly, but there are duplicate 'Customers' showing up in ComboBox1, which is rather annoying. Although I understand that this problem would have to be addressed in a new thread.

It is on the OutgoingUF. And it uses the 'Schedule' WS.

What is the advantage of this code vs. what I have done? Is it more efficient?
Thank you very much for putting time into looking at it though, I greatly appreciate it.

It doesn't seem to be working when I run it...

Yes, that is what I did. That's odd. Is there any other way to remove duplicates from the combobox? Other than that, my code works fine.

I have just downloaded your version and the first and second comboboxes are not loading. This is very peculiar.

Capture.jpg
Yes, as you can see here, when I click the combobox, nothing shows up

That worked much better. Thank you. For some reason I thought I would simply be able to copy the subprocedure and change the names around, but that's not working. Any chance you know what I did incorrectly? This is to fill up the third ComboBox with the PO Number, by the way.

Private Sub ComboBox2_Change()
Dim rng As Range
Dim cl As Range

    If ComboBox2.ListIndex <> -1 Then

        ComboBox3.Clear

        With Worksheets("Schedule")
            Set rng = .Range("A4", .Cells(.Rows.Count, 1).End(xlUp))
        End With

        For Each cl In rng
            If cl.Value = ComboBox2.Value Then
                ComboBox3.AddItem cl.Offset(, 1).Value
            End If
        Next cl
    End If
End Sub

Yes you are correct. So now I have this, but it is still not working... it has been a long day

Private Sub ComboBox2_Change()
Dim rng As Range
Dim cl As Range

    If ComboBox2.ListIndex <> -1 Then

        ComboBox3.Clear

        With Worksheets("Schedule")
            Set rng = .Range("B2", .Cells(.Rows.Count, 1).End(xlUp))
        End With
        
        For Each cl In rng
            If cl.Value = ComboBox2.Value Then
                ComboBox3.AddItem cl.Offset(, 1).Value
            End If
        Next cl
    End If
End Sub

So I changed it to this:

ComboBox3.AddItem cl.Offset(, 2).Value

but it only works some of the time. For instance, it works for the ADMO selection in combobox1, but not Stanley II.
Is this something to do with the

If ComboBox2.ListIndex <> -1 Then

statement?

It has given me this:
$A$2:$B$13

YES! Thank you so much!