Sorry in advance for the long problem description...
I recently had to re-image one of my machines and reinstall all of my apps/development tools. After getting back up to speed, I noticed something strange...
I created a new website project and when I went to add a new Web Form, the “Add New Item” dialog displays only 1 control at the bottom – a “Name” textbox to enter the filename. What I expected was 4 controls – “Name” textbox, “Language” dropdown list, “Place code in separate file” checkbox, and “Select master page” checkbox (this is what appears on another machine).
Also, on the rebuilt machine there is a template called Web Content Form which, if you select it, prompts for a master page in a separate dialog. On the other machine there is only a Web Form template (because the dialog allows you to check the "“Select master page” checkbox" at the bottom).
AND, on the rebuilt machine, once a Web Form was added, the Solution Explorer shows 3 files (filename.aspx, filename.aspx.cs, and filename.aspx.designer.cs).
All of this behavior was sounding "old" (like beta days).
Anyway, looking more closely I also noticed that when I right-clicked on the solution, the context menu contained an "Add" menu item with a flyout that has "New item..." and on the other machine the context menu contained an "Add new item..." menu item (no flyout).