You can use a module in the Worksheet "SelectionChange". Right click on the worksheet and choose "View Code". Paste this code into the VBE. Do this for each worksheet where you need it done.
Private Sub Worksheet_Change(ByVal Target As Range)
Dim rng As Range
Set rng = Intersect(Target, Range("B3"))
If rng is Nothing Then
Dim cl as Range
For Each cl In rng
Instead of having just Range("B3"), you could use Union of several cells, and then it would be combined into one.
old, slow, and confused
but at least I'm inconsistent!
For some reason I couldn't get your code to work. But from looking at your and researching other options I came up with this.
Private Sub Worksheet_SelectionChange(ByVal Target As Range)
If Target.Cells.Count = 1 Then
If Target.Address = "$L$1" Then
ElseIf Target.Address = "$L$2" Then
ElseIf Target.Address = "$L$3" Then
Private Sub Worksheet_Change(ByVal Target As Excel.Range)
If Target.Column = 1 Then
ThisRow = Target.Row
If Target.Value > 100 Then
Range("B" & ThisRow).Interior.ColorIndex = 3
Range("B" & ThisRow).Interior.ColorIndex = xlColorIndexNone