I have two Magento 1.4.2 installations that were recently patched with SUPEE-7405.
As a result of that, it seems that the System > Configuration > Design page is missing 3 tabs: HTML Head / Header / Footer.
These options are all a part of the Page module but that doesn't seem to have changed in the patch at all. Also, nothing else seems to be missing.
Could anyone help point me in the right direction in terms of debugging this ? I already checked the system.xml of the Mage_Page module and it's all there, there no rewrites for the module, and of course all caches were cleared.
Any ideas on how to get to the bottom of this would be highly appreciated.
I managed to fix it.
The problem was that the site was overwriting Mage/Page/etc/config.xml (in order to add a new template) - which is totally wrong of course.
Before the patch however, this worked fine - after the patch, I had to copy the system.xml too in the same override module (local/Mage/Page/etc/system.xml).
local/Mage/... overriding, while good enough for prototyping / testing / hot-fixing, is considered a bad practice or anti-pattern if you will (as you yourself discovered hard way), only small step away from changing core. To extend core functionality create your own extensions, because otherwise you'll end up in the world of hurt.
Yep, the problem with /local/Mage overrides is that you are copying the complete file over to make often single function changes. Upgrade and all the functions in that override are a previous, often incompatible version at war with core.
Create a module so you change only the item you want changed, makes for a lot simpler testing on doing your DEV test upgrades because it's only that one or two functions that may conflict, not everything that's contained in the file. Then when you do a LIVE commit, you shouldn't be in danger of killing your income stream.