Comment 2 for bug 1405897

that dropbox is not showing the icon in wingpanel( task bar as u named it).
it is because dropbox decided not to use gtk anymore.
this is on luna and on freya. it will not change because of dropbox decision.

if you just install it, it will still work open terminal en type: 'dropbox status'
you will see that is still works and synchronizes, that only the icon is not precent anymore.

tip: next time make 2 separated bug reports it is easier