- Display snapshot first when double-clicking on an item, to make it consistent with the View button

- Check DOI field for View button
- Return false in Zotero.Item.getLocalFileURL() if file is missing rather than throwing error

chrome/content/zotero/bindings/itembox.xml

@@ -260,6 +260,18 @@
 								}
 							}
 							
+							// If that fails, try the DOI field
+							if (!spec) {
+								var doi = this.item.getField('DOI');
+								if (doi) {
+									// Pull out DOI, in case there's a prefix
+									doi = doi.match(/10\..*/);
+									if (doi) {
+										spec = "http://dx.doi.org/" + encodeURIComponent(doi);
+									}
+								}
+							}
+							
 							if (!spec) {
 								break testView;
 							}

chrome/content/zotero/overlay.js

@@ -1907,6 +1907,20 @@ var ZoteroPane = new function()
 				var item = ZoteroPane.getSelectedItems()[0];
 				if (item) {
 					if (item.isRegularItem()) {
+						var uri = Components.classes["@mozilla.org/network/standard-url;1"].
+								createInstance(Components.interfaces.nsIURI);
+						var snapID = item.getBestSnapshot();
+						if (snapID) {
+							spec = Zotero.Items.get(snapID).getLocalFileURL();
+							if (spec) {
+								uri.spec = spec;
+								if (uri.scheme && uri.scheme == 'file') {
+									ZoteroPane.viewAttachment(snapID, event);
+									return;
+								}
+							}
+						}
+						
 						var uri = item.getField('url');
 						if (!uri) {
 							var doi = item.getField('DOI');

chrome/content/zotero/xpcom/data/item.js

@@ -2565,10 +2565,12 @@ Zotero.Item.prototype.getLocalFileURL = function() {
 	}
 	
 	var file = this.getFile();
+	if (!file) {
+		return false;
+	}
 	
 	var nsIFPH = Components.classes["@mozilla.org/network/protocol;1?name=file"]
 			.getService(Components.interfaces.nsIFileProtocolHandler);
-	
 	return nsIFPH.getURLSpecFromFile(file);
 }