I just was typing furiously fast and missed an s on my tag system-tweak, there. Now I can't change it! Does it bother you as much as it bothers me that it's singular and every other tag is plural?
Personally, I don't think there's much use in creating that tag whatsoever. We already have: tweaks.
Still, it is very broad, and somewhat redundant. Adding the tag tweaks (or system-tweaks for that matter) doesn't really help to refine a question in any way. You definitely want to tweak something specific, so therefore use the specific tag for this (e.g. the Windows Explorer, thumbnails, etc).
Because of this, I retagged your question to use tweaks instead, but expect a request to have that tag removed soon :)