Cannot edit Title Property when Web Part Page.

To repro create a Document Content Type using Web Part Page.

Add Content Type into Document Library

Create Page

Select Page and in the ribbon 'Edit Properties'

(No Title Field)

Cancel, select View Properites

You see Title, but cannot change the value?  Is this by design? Why?

We are using CSOM to load all .aspx page in a document library into a menu, but would like to use the Title property, but it is 'null' and no why to change the value.

The Title Bar web part only changes the Page breadcrumb, but not the Title property field of the document itself.

Suggested workaround???