Tu dupliques les procédures :
Private Sub ComboBox1_Click()
Sheets(ComboBox1.Value).Activate
End Sub
Private Sub ComboBox2_Click()
Sheets(ComboBox2.Value).Activate
End Sub
Private Sub ComboBox3_Click()
Sheets(ComboBox3.Value).Activate
End Sub
Private Sub ComboBox1_DropButtonClick()
ComboBox1.Clear
ComboBox1.AddItem Sheets(2).Name
ComboBox1.AddItem Sheets(3).Name
End Sub
Private Sub ComboBox2_DropButtonClick()
ComboBox2.Clear
ComboBox2.AddItem Sheets(4).Name
ComboBox2.AddItem Sheets(5).Name
End Sub
Private Sub ComboBox3_DropButtonClick()
ComboBox3.Clear
ComboBox3.AddItem Sheets(6).Name
ComboBox3.AddItem Sheets(7).Name
End Sub
A+