This is odd...my calculator changed fonts to a smoother, helvetica-like font. The top of the characters rests at the horizontal "line" of the display window, leaving a gap at the top.
I would post pics, but I don't have flickr or anything. The weird part is, I don't do mods or anything. So how did it change? Does anyone else have the same problem?
-=|Mgkwho
Widgets are like little web pages. Sometimes one my my calculator buttons fails to load (some kind of timeout?) and I get a Safari style question mark on that button until it refreshes when I next click. In your case, maybe the CSS stylesheet of the calculator did not load?
Try clicking the calc, then hit Command-R -- same way you would reload a Web page.