Windows 7 - Game "hardware cursor" disappears after changing text size

I'll start out here by stating a problem I finally solved and then my question:

For months now I've been fighting that my hardware cursor disappears in World of Warcraft on my home theater system and time I switch modes to full screen and sometimes even in windowed mode and the reason for this is apparently due to me setting my display text size to 150% or 125%. I did find via some searching WoW customer service forums that if I set it back to 100% (default) OR 149% customized, my hardware cursor works again. I'm going to leave it at 149% because I really do need the larger text size on my HDTV and using 149%, I don't have to change back to normal, log out, log in, then start my game.

I'm glad I found this solution - but my question is, WHY is this an issue on Windows 7? Why does 149% work??

I did some searching and couldn't find any reports of this on XP - and as far as I can remember it only started happening to me when I upgraded my XP to Windows 7. I'm hoping Microsoft recognizes this as a bug and will fix it someday.

Thanks in advance!

This has to do with DPI scaling. Technically, when you change DPI different images should be used (higher DPI - higher quality image).
150% probably is that border where image should be changed. Likely, in your case that image is missing or somewhat corrupt (or might be a Blizzard's bug).

But Microsoft knows about problems with scaling. In Windows 8 Dev. Preview, at least in Metro part of it, scaling is done in a different way.

Thanks for your answer - now that you explain it, I'm betting the problem is Blizzard's because the cursor is obviously a custom cursor. From what you say, if they don't have the right DPI, then it won't show. I'm going to search through their files and see if I can find their cursor image and mess with it (just for the fun of it). Not that I really need to "fix it" since I do have the "149%" solution - but I just really hate blindly fixing things and not know the logic behind it.
I'm guessing this DPI scaling was new and/or different in Windows 7 -vs- XP? I swear I never had this issue in XP.