Just tried on Ubuntu 12.04 in Unity from Windows 7 and worked perfectly fine. Can you tell me more about your environment?
Please specify the keyboard layout in use on client and on server and also:
– Whether the problem arises connecting to a physical or a virtual display.
– Remote and local Windows/Mac/Linux version (Windows XP/7/8, OS X 10.x, Ubuntu xyz, Mint x.y, etc.).
– If on Linux, desktop version (GNOME. KDE, whatever) on client and on server.