Pages: "Manual HTML" Option Does Not Appear When Creating Page Within Page Folder

In AdminCP, clicking 'Add Page' in the Pages section correctly displays the option to create either a "Page Editor" or "Manual HTML" page...

^ Click this, and...

^

^ ... this appears.

However, the popup does not display when a page is created via the "+" icon via a Page Folder...

^ ... clicking this button simply directs you to the "Page Editor" page creation page, and does not give you the option to select "Manual HTML".