Dropbox indicator menu went missing in 13.10. How to get it back?

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http://askubuntu.com – I installed Ubuntu 13.10, then installed Dropbox from Ubuntu Software Center. Yet starting Dropbox seems to have no effect, and the Dropbox icon doesn't appear in the top-right indicator area like it normally does. Dropbox is apparently running, but the indicator/menu doesn't show up. (HowTos)