In bug report submission form of FreeBSD Bugzilla there is 'Description' field and it has 'Preview' functionality. It is used to preview how sentences in the field is displayed when bug report is submitted, especially how link to other bug, comment, SVN commit and review is displayed. But sometime nothing is displayed when 'Preview' window is selected. The conditions under which the problem happens is totally unclear. For example it can happened with one sentences composed of 20 words or so and not including any type of links. So I
doubt the problem may have nothing to do with input sentences and something else may be the source of it.