Comment 7 for bug 405413

For myself, I also see existing connections disappear from the list -- for example, my "Auto Home" connection, where Home is the SSID.
All it takes for me to see this happen is the following:
Connect to the network using the normal menu, and enter passphrase.
Then open the connection editor, check "available to all users" for Auto Home, and hit apply.
For me, the connection immediately disappears from the list in the editor; the next time I use the menu to connect, it asks for the passphrase again, as if it has never before connected to that network.
it is entirely possible these are two different issues, however.