MS Excel Form Chebbox Change Font Size

From reading around, it appears that the font in Form checkboxes in Excel can't be modified, and to use ActiveX checkboxes instead.

However, I'm looking at a spreadsheet that someone else created (who has long since departed) where the Form checkbox definitely has its font modified. I'm not sure how they were able to accomplish this. Any ideas?

In the meantime, I've copied their form into my spreadsheet as a workaround. The default form checkbox just has too small of a font, that's all I need to modify.