If enabled in policy AnyConnect disables and re-enables the Connections tab on a graceful disconnect of the VPN client. The trouble arises when a user abruptly closes the AnyConnect VPN client. The "Connections" tab is left hidden and subsequent connect/disconnects of the VPN client do not restore it.
Delete the registry key:
[HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Internet Explorer\Control Panel]