It does not seem to work.

I implemented a base class in the way below , and now it seems to work. Must have picked it up here earlier.

Anyway. Go figure.

Public Class dgv
    Inherits DataGridView
    Protected Overloads Overrides Function ProcessDialogKey(ByVal keyData As Keys) As Boolean
        If keyData = Keys.Enter Then
            Return Me.ProcessTabKey(keyData)
        Else
            Return MyBase.ProcessDialogKey(keyData)
        End If
    End Function
    Protected Overrides Sub OnCellEnter(ByVal e As System.Windows.Forms.DataGridViewCellEventArgs)
        If Me.Columns(e.ColumnIndex).ReadOnly = True Then
            SendKeys.Send("{TAB}")
            Exit Sub
        End If
        MyBase.OnCellEnter(e)
    End Sub