private void buttonNotes_Click(object sender, EventArgs e)
        {
            if (this._event != null)
            {
                TextInputDialog tid = new TextInputDialog("Notes", this._event.Notes);
                // Dialog zentrieren
                tid.Location = new Point((this.Size.Width) / 2 - (tid.Size.Width) / 2, this.Location.Y);

                if (tid.ShowDialog() == DialogResult.OK)
                {
                    this._event.Notes = tid.Value;
                }
            }
        }
        private void buttonLocality_Click(object sender, EventArgs e)
        {
            if (this._event != null)
            {
                TextInputDialog tid = new TextInputDialog("Description of Event Locality", this._event.LocalityDescription);
                // Dialog zentrieren
                tid.Location = new Point((this.Size.Width) / 2 - (tid.Size.Width) / 2, this.Location.Y);

                if (tid.ShowDialog() == DialogResult.OK)
                {
                    this._event.LocalityDescription = tid.Value;
                }
            }
        }