There's a new menu above the metadata pane. Double-clicking on the item is also equivalent to View.

Is the URL in the URL field a file:// URL?

OK, so this is a little complicated.

First, that's not web-based storage. That's a network share.

More importantly, the URL field is meant for the canonical URL for the item—the location of its primary representation on the web—and not something specific to your use. View Online is designed with that in mind, and it won't take you to a file:// URL from that field.

Your usage is a bit unusual, but you should really be using an attachment. On Windows, Attach Link to File should work fine for this, since that's what you're doing. In the next 2.1 build, as long as you're attaching PDFs, they'll be opened before either the snapshot or the URL field when you double-click the item (and View PDF will show up as the first item in the Locate menu for such items). In 2.1b7 the snapshot will be opened, since the current code favors snapshots with a URL matching the parent item, so if you switch to using attachments you'll have to expand the parents and double-click the attachments directly until the next build is out.

Double-clicking the item will cease to open the file:// URL in the next build, since it's meant to be equivalent to the first action in the Locate menu, which in the absence of an attached PDF is View Online.

You can also click the URL label in the metadata pane to take you to the URL in the field. This currently works for file:// URLs as well, but you're still using that field in a way it's not meant to be used, and ongoing changes to Zotero that assume proper usage could easily break things that you expect to work.

I doubt that someone from the Zotero team would have recommended this - the solution for this issue have always been links, which have existed since Zotero 1.0 (and probably before) - the problem with making use of features in a way that's not intended is, as Dan notes, that it may be broken by future developments. In addition, you should be aware that this will mess with many of the citation styles on the repository.

Attach link to file is to attach a link to a file (located somewhere on your disk or the internet) to an existing item. It is active when you have any bibliographic item selected, but not for files, attachments, or notes.

huh - these are items in a group library, right? I can actually replicate that - I don't think that's intended and I don't remember that being the case.
Someone with more experience dealing with groups help me out here

edit: see below - I was wrong - it's intended and has always been the case.

Thanks for your responses guys.

Yes it is a group library. It surprises me that there are not many other groups that want to have a single copy of an item in say a network drive or web storage. Is that what you are saying is rare?

Is there a particular reason why the 'link to file' function cannot be activated for group libraries? This would seem to be a very simple solution for the workflow but there may well be technical reasons why it cannot be implemented.

Like us, all the groups we know that have group libraries use them as a 'within organisation' tool as they cannot afford Endnote and Zotero meets their needs - they are environmental groups, public and NGOs.

This means that like us, they always have access to the same file path as the storage is accessible to all users of the organisation.

The file path option opens the document immediately for us, whereas if we use a http, it opens a page to download the item so it is nowhere near as convienient. For the time being we will continue to use the URL field, however a solution more in line with indended use would be appreciated in the future.

You should know that your product is assisting many environmental groups here in Australia that could otherwise not afford to manage their information this effectively. This will in time result in better quality investment decisions and therefore environmental outcomes. So your good work is having some far reaching benefits - keep it up!

Cheers
Mat