Update: a work-around was added in the Copy client so the instructions below are no longer needed if you use the latest Copy!
The Copy.com client indicator menu doesn't work properly in Ubuntu 14.04 and 13.10 due to a bug in libdbusmenu.
This bug was fixed in Ubuntu 14.10 and I'm not sure when it will be fixed in older Ubuntu versions but you can get the Copy.com indicator menu to work right now in Ubuntu 14.04 and 13.10 by using the fix / work-around below.
First of all: be sure to delete Copy versions eventually installed manually.
tar -xvf libdbusmenu-gtk*
sudo cp /tmp/libdbusmenu-gtk*/* /PATH/TO/COPY-FOLDER/
The instructions above will download libdbusmenu-gtk compiled with the fix and copy it to the copy-client folder. For the last command, replace "/PATH/TO/COPY-FOLDER/" with the path to where you've installed Copy. If you've used the Copy PPA, the path is /opt/copy-client/
This work-around / fix includes libdbusmenu-gtk built by me. If you want to build it yourself, see HERE.