private void AddBoldImpl()
{
var surroundedTextTpl = SurroundSelection(SelectionStart, SelectionStart + SelectionLength, ReplyBody, _boldFormattingString);
ReplyBody = surroundedTextTpl.Item3;
SelectionStart = surroundedTextTpl.Item1;
SelectionLength = surroundedTextTpl.Item2 - surroundedTextTpl.Item1;
}