Salutations,
I believe you're using a multicolumn listbox. If you type in the necessary text, you can always bold it by going to the toolbar section near the puase button. In there, it has "style" and you can select bold (currently this button is labeled 13 pt application font" for me).
Once this is set, it seems to remember the formatting for this location. That way your column and row headings will always be bold.
Is there a quick way to do this? My quick investigation didn't turn anything up. The property node theory, which is one of the best ways to deal with such tasks, doesn't seem too useful. But, I could be wrong.
Hopefully this helps,
Sincerely,
ElSmitho