Worksheet_SelectionChange Event

I found this code on one of my many searches, that works great.

(can't remember where I got it or who wrote it, (My deepest apoligies to the author))


Public pRule

Sub butRulerToggle_Click()
pRule = Not pRule
Selection.Select
End Sub

Private Sub Worksheet_SelectionChange(ByVal Target As Range)
If pRule Then
For Each aCell In ActiveSheet.UsedRange
If aCell.Interior.ColorIndex = 27 Then aCell.Interior.ColorIndex = xlNone
Next
On Error Resume Next
For Each aCell In Application.Intersect(ActiveCell.EntireRow.Cells, ActiveSheet.UsedRange)
If aCell.Interior.ColorIndex = xlNone Then aCell.Interior.ColorIndex = 27
Next
End If
End Sub

My question:
This works in a sheet module. How can I put it in the This Workbook module so it works on all sheets.

By the way, what this does is highlight the whole row on a clik of a cell, leaving any color formating that was initially there alone.

Very useful if you are looking at say A10 and then want to look at Z10 without losing focus on the row.