GTK+ apps runing as root won't use theme specifies by kcm-gtk

[dw40]

Binary package hint: kcm-gtk

I'm running Kubuntu 9.10 alpha 3 with package kcm-gtk-0.5.2-0ubuntu1 installed. Application such as Synaptic, running as sudo, will not use GTK+ themes specifies by kcm-gtk (listed as GTK+ Appearance under Kubuntu System Settings). It will use the specified theme just fine when running as a normal user. It seems like the config file .gtkrc-2.0-kde4 in the user's home directory works fine, but the same file in the root directory doesn't do anything. I found that creating a sym link, in the root directory, called .gtkrc-2.0 pointing to .gtkrc-2.0-kde4 in the same directory, solved this problem. The question is, why this happens to apps running as sudo/root but not to normal user?