For a while I was puzzled by your experiences, cb, because when I use ctrl + and - in Firefox, the letters on the cross get bigger and smaller just like the rest of the page. But then I discovered that Firefox has an option to control what happens when you use ctrl + and -. The way my Firefox was set up, the screen simply zooms in and out, so everything grows and shrinks to the same extent, whether text or image or whatever. Presumably you have things set up to "Zoom text only". In this mode, the letters on the cross do indeed go weird and unreadable. Sorry!
I think I was trying to change things so that the letters on the cross would change size in line with the text on the page (which can be adjusted in various ways in various browsers). But I obviously never got it working. I think I may have given up the idea as too complicated, given all the things that have to change if the letters change in size. But it seems I forgot to remove the partial changes I had made. I'll fix this up soon.
As for the other problems people have mentioned, I don't know what's causing these things, but I'll keep investigating.
