If you using Dropbox client and you would like full system tray integration unfortunately you can not install a package that will work without issues with latest versions of dropbox client.
Solution is to download, compile and install kfilebox from source, but since kfilebox is unmaintained for long time I found this fixed version on github page: https://github.com/gtgt/kfilebox.
To compile successfully you will need few perquisites installed:
apt-get install build-essential libqjson-dev git
Then you need to clone the repository and compile and install:
git clone https://github.com/gtgt/kfilebox cd kfilebox qmake make make install
If all went well when you start kfilebox you will see this nice integrated icon in your system tray.