Problems with Existing Contact field behaviour

1.0 Problem/Motivation
There are two, probably separate, problems with the behaviour of the Existing Contact field on a Webform.

1. If the Form Widget is set to Static, then setting Display Contact Name to Yes does not work - the field remains hidden.
2. If the Set Default Contact From is set to Current User, then the form is populated with the current user's details, but when the form is submitted no Contact Id is sent, and a new contact is created rather than the existing one being updated.

The combination of these problems means that if a webform is created with the default settings out of the box, the form comes up with the current user's details, but when a change is made and the form redisplayed, then the changes have not been saved (because a second Contact was created). In my case it took quite some time to realise that this was what was going on.

2.0 Detailed steps to reproduce
Running: Webform 6.0.0; Webform CiviCRM 8.x-5.0-beta4.

• Create new webform
• Enable CiviCRM in Settings - defaults to a single Contact 1
• Save
• View the Form and make a change to one of the fields shown.
• Redisplay the Form - no change has occurred.
• Search in CiviCRM will show that a duplicate, modified, Contact has been created.

• Go to Build, and Edit Existing Contact
• Change Display Contact Name to Yes
• Save and View form - The Existing Contact Field is not shown.