This thread is ok, but it doesn't answer the basic issue

admin>catalogue>product types>Edit Layout is always empty

So you can never change "Show Additional Images = 0" to 1 since the page and database seem to be missing a value

I even checked a brand new default install of zencart and the admin page is blank on that install as well, so its not something in my shop that is altered by me or my theme or any added modules or customisations..

What to add and how do I add the values Show Additional Images = 0 or Show Additional Images = 1 to the admin page admin>catalogue>product types>Edit Layout do I manually add something to the mysql ?

Does anyone have anything on that page admin>catalogue>product types>Edit Layout what does it display ?