We recently upgraded from SharePoint 2007 to 2010. There are a number of customization we made in the environment, and it seems that something is causing a problem when a user tries to create a document library based on a template (.stp). Here is the scenario:
A user saves a list as a template. It shows up in the List Template Gallery (_catalogs/lt) as expected. The user then goes to create a new list (_layouts/create.aspx or the Silverlight counterpart). The list shows up and the user is able to create new instances of the list.
When the user tried to do the the same things with a document library, it does get saved to the List Template Gallery, but does not show up when creating a new document library.
I tried this process on a clean install of SP2010 and it works fine with document libraries. I tried downloading the .stp file created from the clean environment and uploading into the tempalte gallery in our custom environment, and it doesn't show up either.
Another note of interest is that if I generate the URL for creating a new instance of the list manually, by filling in the template's name and featureID into /_layouts/new.aspx?CustomTemplate=test%20template%20lib%2Estp&FeatureId={...}&ListTemplate=101 everything seems to work fine. So the only thing that's not working is that the user can't see the option on _layouts/create.aspx or the Silverlight counterpart.
What could cause this type of behavior?
UPDATE: Did some more troubleshooting and figured out that this only happens on upgraded sites. If we create a new subsite under the upgraded site, it has no trouble seeing all the list and doc lib templates from the gallery. Even ones saved from the patent site.