I have the same problem as the original question. When I open Dropbox it just goes to the explorer window. There is no other App I can see. So how to I change the settings?
In my case I want some online files to be available on my laptop. When I first installed and opened Dropbox I got the choice of what folders/ files I could see, but subsequently all I can do is see the ones I chose to be off line.
The only way I can find to do this is to uninstall and reinstall, which is ludicrous. there must be another way, The top says solved but I don't see a solution to the original question and this is 4 years later.