Use of with end with in VB

Private Sub Command1_Click()
With Form1
Select Case Combo1.ListIndex
Case 0
.BackColor = vbRed
Case 1
.BackColor = vbWhite
Case 2
.BackColor = vbGreen
Case 3
.BackColor = vbBlue
Case 4
.BackColor = vbBlack

End Select
End With

End Sub

Private Sub Command2_Click()
End
End Sub

Private Sub Form_Load()
With Combo1
.List(0) = "red"
.List(1) = "white"
.List(2) = "green"
.List(3) = "blue"
.List(4) = "black"
End With
End Sub