I've createda small code which turns a command button red after pressing it. There are multiple command buttons in the array, all called C2. There are also the C1's and the C0's. This is the code:

Private Sub C2_Click(a As Integer)
C2(a).BackColor = &HC0&
C2(a).Enabled = False
C1(a).Enabled = False
C0(a).Enabled = False
puntos = puntos + 2
PPP.Caption = puntos
End Sub
Whenever I run it, everything works fine except for the backcolor, which only works when pressing the first one. After a little experimenting I found out that no matter whether I change it to something like:

C2(3).BackColor = &HC0&
It still won't work. What's more is that if I do it like that the first one (C2(0)) won't work.

Any idea as to why this happens?