Hi all! I'm having some issues with a Combo Box that I cannot for the life of me figure out. I am trying to have a single Combo Box that jumps around to whichever cell the user selects in a specific column on a spreadsheet and to then dynamically change the LinkedCell of the Combo Box to the selected cell. I've gotten everything working except for the LinkedCell part - here's the code I'm currently running with:

PHP Code: 
Private Sub Worksheet_SelectionChange(ByVal Target As Range)
    
    Dim WB_Timesheet As Workbook
    Dim WS_Timesheet As Worksheet
    Dim NumberOfCellsSelected As Integer
    Dim CB As Shape
 
    Set WB_Timesheet = Application.ActiveWorkbook
    Set WS_Timesheet = WB_Timesheet.Sheets("Timesheet")
    Set CB = WS_Timesheet.Shapes("ComboBox_ClientMatter")
    NumberOfCellsSelected = Target.Cells.Count
    
    If NumberOfCellsSelected > 1 Then
        CB.Visible = False
    ElseIf Selection.Count = 1 Then
        If Not Intersect(Target, Range("C6:C10000")) Is Nothing Then
            Dim Position_Left As String
            Dim Position_Top As String
            Dim CB_Height As String
            Dim CB_Width As String

            Position_Left = ActiveCell.Left
            Position_Top = ActiveCell.Top
            CB_Width = ActiveCell.Width + 15
            CB_Height = ActiveCell.Height + 2
                        
            With CB
                .Visible = True
                .Left = Position_Left
                .Top = Position_Top
                .Width = CB_Width
                .Height = CB_Height
                .ControlFormat.LinkedCell = ActiveCell.Address
            End With
        Else
            CB.Visible = False
        End If
    End If
End Sub 
The code keeps bugging out on the line of ".ControlFormat.LinkedCell = ActiveCell.Address". I've tried what feels like a million different formulations of this (including not using the ".ControlFormat" portion, messing around with the stuff after the "=", etc.), but I keep getting the same run-time error '438'. If anyone could help me figure out what I'm doing wrong I would be extremely grateful.

Also, as an aside, if anyone knows how I can use VBA to (i) put the cursor into the Combo Box and (ii) make it to where, upon initially selecting/targeting the Combo Box, it selects all of the text therein (i.e., something akin to pressing "Ctrl+a"), I would also very much appreciate that as well. (This would just be an added bonus and I'm mainly just looking to figure out how to alter the linked cell.)