I'm using Gnome Shell in Ubuntu 11.10. I ran into a problem with Ubuntu when I tried to share my network connection. It sat at connected, failing, connected, failing, continuously. Because the connection was not fully working, the "configure" button was grayed out. I was unable to select it in order to go into IPv4 settings and switch it back to regular DHCP.
The fix? Logged out, logged in to another desktop environment which contained the features I needed, and switched it back.
Why are these features missing? Why can I NOT select "configure" at any time I want? This is extremely counter productive.