I recently noticed a bug when you start GNU Emacs win32 after starting Windows Magnifier: Emacs' cursor becomes a single-pixel "caret" instead of the box cursor. This makes the cursor very hard to find.
I usually leave Emacs' cursor at the default (
box) because this is so much easier to see, especially if you also enable
blink-cursor-mode (though that's a matter of taste, I suppose). The default settings also set the cursor to a
hollow box when the
window (or the entire
frame) is inactive.
Really, a text editor is unusable with a "caret" or bar-shaped cursor.
The following behaviors are observed with this bug:
cursor-typevariable: it is always as-if the value were
(bar . 1)(a vertical bar, one pixel wide)
HKCU\Control Panel\Desktop\CaretWidthalso has no bearing on the cursor shape (though this key is great for setting the cursor thickness in other Windows programs...)
So, the work-around for this is to start Emacs before you run Magnifier (especially: make sure the Windows Accessibility feature that starts Magnifier when you log in, is turned OFF).
As far as I can tell, there is no bug report for this. I may file one when I get around to figuring out GNU's bug-tracker.