Auto-populate Combobox - Extracts Unique Distinct Values From Column

The code below extracts unique distinct values from column A, except cell A1. Then the code adds the extracted unique distinct values to the combo box.

Sub FilterUniqueData()
Dim Lrow As Long, test As New Collection
Dim Value As Variant, temp() As Variant
ReDim temp(0)
On Error Resume Next
With Worksheets("Sheet1")

[Code]....

The vba code below copies the selected value to cell C5 whenever the combobox is selected

Copy the code into a standard module.Assign this macro to the combobox

Sub SelectedValue()
With Worksheets("Sheet1").Shapes("Drop Down 1").ControlFormat Worksheets("Sheet1").Range("C5") = .List(.Value)
End With
End Sub

Vba code belows instanly refresh the combobox when values are added/edited or removed from column A,

Private Sub Worksheet_Change(ByVal Target As Range)
If Not Intersect(Target, Range("$A:$A")) Is Nothing Then
Call FilterUniqueData
End If
End Sub

My problem is this:

Everything will be working fine if the all combobox and data can be found in 1 sheet, but how could i make some tweaks if the combo box is located in sheet 2 provided your data to be populated is in sheet 1, i tried everything but the combobox doesnt update,