[pudquick]

This is the first comment in this discussion I've seen that is actually interesting and might provide an explanation.

The Dropbox file status symbols are a -big hack-. Up until OS X 10.10, for instance, the file browsing interface didn't provide per-file badging at the OS API level. So they literally had to patch the running Finder process to do this.

I wouldn't be surprised to learn something similar is going on with Windows Explorer.

[ryanackley]

No, Windows provides a well-documented way to customize folder and file icons inside Windows Explorer (their equivalent of Finder).

[nodata]

They were patching the running Finder process? wtf?

[cpach]

See this blog post from 2011: http://mjtsai.com/blog/2011/03/22/disabling-dropboxs-haxie/

[mrpopo]

I know my company has had many problems that were pinned down to Dropbox hooking some Win32 API functions that we use. I am not familiar with the semantics of hooking, but could it be related to that?

[neckro23]

Windows has a standard way of doing this, no? I've seen other Windows apps like TortoiseSvn do icon overlays too.