No Dropbox icon in the indicator panel?
Found a solution at the comment #7 from the Ubuntu bug:
Install package
sudo apt-get install libappindicator1
Log out, and then log back in (or issue
dropbox stop && dropbox start
at the command line)
If I recall correctly there is an unfixed bug in the dropbox package for 13.10. Cf. launchpad. This is at present a confirmed, but unassigned bug.
If this is not that bug, then read this question.
There is another issue that has popped up recently.
This is with regard to 14.04, being that,
Dropbox runs in the background but does not show the indicator panel icon even when appindicator1 is installed.
The only work around i found was to re-install Dropbox by getting the .deb file form the link: Download Dropbox