I am using Kubuntu 14.10 on an AMD 64 machine.
I have followed the guidelines in
and installed Dropbox 3.0.3 using method 1.
The white Dropbox icon shows up on the system tray. Right clicking on the icon opens the context menu but it cannot be used because it is transient, i.e., it disappears before a selection can be made.
This means, among other things, that Dropbox Preferences cannot be viewed, set, or changed.
My previous version of Dropbox had a system tray icon with a usable context menu and also a left-click menu that opened the Dropbox folder in dolphin. There is no left-click menu in Dropbox 3.0.3.
Now that Dropbox uses Qt, I would have thought that more rather than less functionality would be available in KDE/Kubuntu.