UWC behavior

On most occasions when the configuration is set correctly, the UWC (Communications Express) should render just fine like the one shown below:

At times, the following will be observed (with Mail tab missing):

When will this happen? There are a few likely cases:

1. Mail Host is set incorrectly

2. local.webmail.sso.uwcenabled has not been enabled

3. service.imap.enable has not been enabled (Webmail requires IMAP connections)