Private Sub Form_Load()
 Timer1.Interval = 50
 Timer1.Enabled = True
End Sub
 
Private Sub Timer1_Timer()
Dim C As Control
 
For Each C In Me.Controls
If TypeOf C Is TextBox Then
 If C = Me.ActiveControl Then
  C.BackColor = vbYellow
 Else
  C.BackColor = vbWhite
 End If
End If
Next
 
End Sub