protected override void OnMouseClick(MouseEventArgs e)
{
base.OnMouseClick(e);
bool isTrailingHit;
bool isInside;
HitTestMetrics hitTestMetrics = this._textLayout.HitTestPoint(e.X, e.Y, out isTrailingHit, out isInside);
if (isInside)
{
bool underline = _textLayout.GetUnderline((int)hitTestMetrics.TextPosition);
_textLayout.SetUnderline(!underline, new TextRange((int)hitTestMetrics.TextPosition, 1));
Render();
}
}
