Unexpected behaviour of "For Each wks In ActiveWindow.SelectedSheets", it affects more column that it should be - excel

Question

i did this code that works pretty well exept the last part:
The behaviour of last part should be that ".Interior.Color" and ".Value" affected until the last populated column, instead it affects the first cell of many other columns. Any ideas?
Sub Sample_Workbook()
'Creation of new workbook
Application.ScreenUpdating = False
Workbooks.Add
Set wb = ActiveWorkbook
wb.SaveAs ThisWorkbook.Path & "etc.xlsx"
'following variable is declared for sending mail purpose
SourceWorkbook = ActiveWorkbook.Name
Set this = Workbooks("Sample")
Set wb = ActiveWorkbook
Set ws1 = wb.Sheets("Sheet1")
wb.Sheets.Add After:=Sheets(1)
Set ws2 = wb.Sheets(2)
wb.Sheets.Add After:=Sheets(2)
Set ws3 = wb.Sheets(3)
ws1.Name = "Sheet1"
ws2.Name = "Sheet2"
ws3.Name = "Sheet3"
'Model the new excel with the requirements:
Dim Population, Population2 As Range
Dim lastRow As Long, firstRow As Long
Dim sampleSize As Long
Dim unique As Boolean
Dim i As Long, d As Long, n As Long
'following function perfoms all the calculations and copy and pasting
doTheJob x, y, z, num, q
doTheJob x, y, z, num, q
doTheJob x, y, z, num, q
'copy and paste the remaining sheets from the sample files
Workbooks.Open ThisWorkbook.Path & "Sample2.xlsx"
Sheets("Sheetx").Copy After:= _
Workbooks(SourceWorkbook).Sheets(6)
Workbooks("Sample2.xlsx").Close SaveChanges:=False
Application.ScreenUpdating = True
Application.CutCopyMode = False
ws1.Select
wb.Close SaveChanges:=True
End Sub
'these will make the variable available to all modules of this macro Workbook
Public SourceWorkbook As String
Public this, wb As Workbook
Public data As Range
Public output As Range
Public ws1, ws2, ws3 As Worksheet
Public LastCol As Long
Public wks As Worksheet
Public iCol As Long
'FUNCTION
Sub doTheJob(x As String, y As String, z As String, num As Integer, q As String)
'beginning logic.
this.Worksheets(x).Activate
Set Population = Range("a3", Range("a3").End(xlDown))
sampleSize = this.Worksheets("SNOW Reports").Range(y).Value
Set r = Population
lastRow = r.Rows.Count + r.Row - 1
firstRow = r.Row
For i = 1 To sampleSize
Do
unique = True
n = Application.WorksheetFunction.RandBetween(firstRow, lastRow)
For d = 1 To i - 1
'wb.Sheets(z).Activate
If wb.Sheets(z).Cells(d + 1, 50) = n Then
unique = False
Exit For
End If
Next d
If unique = True Then
Exit Do
End If
Loop
Set data = this.Worksheets(x).Range("a" & n, Range("a" & n).End(xlToRight))
Set output = wb.Worksheets(z).Range("A" & i + 1)
output.Resize(data.Rows.Count, data.Columns.Count).Value = data.Value
'THE NEXT LINE IS JUST FOR DELETEING LAST COLUMN PURPOSE
wb.Worksheets(z).Cells(1, 50) = "REF COL"
wb.Worksheets(z).Cells(i + 1, 50) = n
this.Worksheets(x).Activate
Next i
'delete REF COL:
With wb.Sheets(z)
.Columns(50).Delete
End With
'copy and paste header:
Set data = this.Worksheets(x).Range("a2", Range("a2").End(xlToRight))
Set output = wb.Sheets(z).Range("A1")
output.Resize(data.Rows.Count, data.Columns.Count).Value = data.Value
'_________________________________________________________________________________________________________
'copy and paste into new sheet with recorded macro
wb.Activate
Sheets.Add(After:=Sheets(num)).Name = q
wb.Worksheets(z).Cells.Copy Destination:=wb.Worksheets(q).Range("A1")
'create columns and add color and text dinamically
For Each wks In ActiveWindow.SelectedSheets
With wks
For iCol = .Cells.SpecialCells(xlCellTypeLastCell).Column To 2 Step -1
.Columns(iCol).Insert
With Cells(1, iCol)
.Interior.Color = 65535
.Value = Cells(1, iCol - 1) & " - Comparison"
End With
Next iCol
End With
Next wks
End Sub

Answer 1

If I understand what you're aiming to do, the following does what you want.
The code could be approached differently (and possibly made more efficient), if the larger context was known
However, I sense this is just a stage in your development, so have stayed with your approach (wherever reasonable).
' I suggest this goes to the top of the sub (no need for public declaration)
' Note the shorthand declaration: 'lgRow&' is the same as `lgRow as Long'
Dim lgRow&, lgCol&, lgLastRow&
' Replaces the code starting with the next comment
'create columns and add color and text dynamically
For Each wks In ActiveWindow.SelectedSheets
With wks
For lgCol = .Cells.SpecialCells(xlCellTypeLastCell).Column To 2 Step -1
' Insert a column (not sure why you're not doing this after the last column also)
.Columns(lgCol).Insert
' Get last row with data in the column 1 to the left
With .Columns(lgCol - 1)
lgLastRow = .Cells(.Cells.Count).End(xlUp).Row
End With
' In the inserted column:
' o Set cell color
' o Set value to corresponding cell to the left, appending ' - Comparison'
For lgRow = 1 To lgLastRow
With .Cells(lgRow, lgCol)
.Interior.Color = 65535
.Value = .Offset(0, -1) & " - Comparison"
End With
Next lgRow
Next lgCol
End With
Next wks
Note 1: Not sure of the reason, but your code inserts the 'comparison columns' after each column, except the last column (of the copied data). If I understand your intent correctly, I'd assume you want to do this for the last column also. If that's true:
'change this line
For lgCol = .Cells.SpecialCells(xlCellTypeLastCell).Column To 2 Step -1
'To:
For lgCol = .Cells.SpecialCells(xlCellTypeLastCell).Column + 1 To 2 Step -1
Note 2: My code changes write <cell value> & " - Comparison" to all cells in each column, down to the last non-blank cell in each 'compared' column (including blank cells above that). If you want to do that write for all rows in the copied data range (whether cells are blank or not) you could simplify the code by placing the following:
' Insert this:
lgLastRow = .Cells.SpecialCells(xlCellTypeLastCell).Row
'above line:
For lgCol = ....
And remove this:
' Get last row with data in the column 1 to the left
With .Columns(iCol - 1)
lgLastRow = .Cells(.Cells.Count).End(xlUp).Row
End With
Other Note / Pointers:
Recommend Option Explicit at the top of all modules (just saves a lot of debugging due to typos)
There's no need (and it's not good practice) to declare Public variables that are only used locally in a given Sub or Function. Instead, declare same locally (usually at the top of the Sub or Function).
It's good practice to use the leading characters of variable names to ID the data type. Can be any length, but is commonly 1, 2 or 3 chars (coder's preference). e.g. Above I used lg to ID long data types. Similarly, I use in for Integer, st for String, rg for Range, etc.