/// <summary>
        /// Called when the Add Split button is pressed.
        /// </summary>
        private void addSplitButton_Click(object sender, EventArgs e)
        {
            SplitControl newSplit = new SplitControl(this, splitControls.Count + 1);

            if (splitControls.Count > 0)
            {
                SplitControl control = (SplitControl)splitControls.Last();

                newSplit.Location = control.Location.Add(spacing);
                control.ToggleDown(true);
            }

            newSplit.ToggleUp(splitControls.Count > 0);
            newSplit.ToggleDown(false);
            splitControls.Add(newSplit);

            UpdateCountLabel();
        }