Option Explicit

Public swapped As Boolean

Private Declare Function SwapMouseButton Lib "user32" (ByVal swap As Integer) As Integer

Private Sub Worksheet_Activate()
    SwapMouseButton 1
    swapped = True
End Sub

Private Sub Worksheet_BeforeRightClick(ByVal Target As Range, Cancel As Boolean)
    If Not swapped Then Exit Sub
    MsgBox "Event BeforeRightClick (with Left click!) on A1 trapped!"
    Cancel = True
End Sub

Private Sub Worksheet_Deactivate()
    SwapMouseButton 0
End Sub

Private Sub Worksheet_SelectionChange(ByVal Target As Range)
    If Not Intersect(Target, Range("A1")) Is Nothing Then
        SwapMouseButton 1
        swapped = True
    Else
        SwapMouseButton 0
        swapped = False
    End If
End Sub