public void TryInUI() { var form = new Form(); var checker = new global::SIL.Windows.Forms.Spelling.TextBoxSpellChecker(); var box = new TextBox(); box.Multiline = true; box.Dock = DockStyle.Fill; box.Text = "correct wrng correct"; checker.SetLanguageForSpellChecking(box, "en"); form.Controls.Add(box); form.ShowDialog(); }