Got it - sorry for being so clueless!

Code:
    Private Sub CaseViewMenuValue_KeyUp(ByVal sender As System.Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles CaseViewMenuValue.KeyUp
        If e.KeyCode = Keys.Enter Then
            CaseViewMenu.DropDown.Close()
            CaseRefresh()
        End If
    End Sub