Any particular reason why you're still using Wheezy?
I'm on Jessie and if I try the same I get;
Code:
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following extra packages will be installed:
gir1.2-gdesktopenums-3.0 gir1.2-gnomedesktop-3.0 gir1.2-soup-2.4 gnome-shell-common mutter-common
The following NEW packages will be installed:
gir1.2-gdesktopenums-3.0 gir1.2-gnomedesktop-3.0 gir1.2-soup-2.4 gnome-shell-common gnome-tweak-tool mutter-common
0 upgraded, 6 newly installed, 0 to remove and 1 not upgraded.
Need to get 1,621 kB of archives.
After this operation, 11.5 MB of additional disk space will be used.
Do you want to continue? [Y/n]