EditorWithText editor = new EditorWithText();
this.dayView.AppointmentEditor = editor;
editor.AfterEnterEditMode += new EventHandler(this.editor_AfterEnterEditMode);
editor.BeforeExitEditMode += new BeforeExitEditModeEventHandler(editor_BeforeExitEditMode);

private void editor_AfterEnterEditMode(object sender, EventArgs e)
{
    this.dayView.Controls[0].MouseDown += new MouseEventHandler(editor_MouseDown);
}

private void editor_BeforeExitEditMode(object sender, BeforeExitEditModeEventArgs e)
{
    this.dayView.Controls[0].MouseDown -= new MouseEventHandler(editor_MouseDown);
}

private void editor_MouseDown(object sender, MouseEventArgs e)
{
    bool stop = true;
}

Regarding how to set the context menu, see your post of 10/14/08.