After I saw a extension of gnome-shell to move pidgin’s icon to the status bar, I tried to roll my own extension following the extension’s source to move the wicd’s icon to the status bar too. I followed the post Adding pidgin icon to gnome-shell status tray.
All I did is just to change the name of pidgin to wicd. After reboot my gnome-shell, it worked. Wicd’s icon appeared in status bar(top bar).
package url: https://aur.archlinux.org/packages.php?ID=54572