To keep this slightly on topic, I'll refer you back to an earlier post about debugging generated HTML.

However, in this case, it's also important to recognize exactly what HTML is, and isn't intended to do.

HTML is a way of placing extra information in a text file, to describe what the content is, in a way that can be easily interpreted by programs. You can place suggestions in the file about how you wish for the page to be displayed, but they are not strict rules.

If the browser can't keep the table within the confines of the screen, there is no requirement that it do so. It may be displayed on a cell phone, or use a large font, or have too much text, or for whatever reason, just not easily fit.

I personally see no reason for having the table in the first place -- it's one cell wide. It's not tabular data. If all you wanted were borders around items, you can achieve the same effect using CSS.