diff --git a/chrome/content/zotero/xpcom/data/itemFields.js b/chrome/content/zotero/xpcom/data/itemFields.js
index bd82d1b107..a2f4e5621c 100644
--- a/chrome/content/zotero/xpcom/data/itemFields.js
+++ b/chrome/content/zotero/xpcom/data/itemFields.js
@@ -379,7 +379,8 @@ Zotero.ItemFields = new function() {
 	function _fieldCheck(field, func) {
 		var fieldID = self.getID(field);
 		if (!fieldID) {
-			throw ("Invalid field '" + field + (func ? "' in ItemFields." + func + "()" : "'"));
+			Zotero.debug((new Error).stack, 1);
+			throw new Error("Invalid field '" + field + (func ? "' in ItemFields." + func + "()" : "'"));
 		}
 		return fieldID;
 	}
diff --git a/chrome/content/zotero/xpcom/data/items.js b/chrome/content/zotero/xpcom/data/items.js
index e8fddb1ef1..abc500e8a4 100644
--- a/chrome/content/zotero/xpcom/data/items.js
+++ b/chrome/content/zotero/xpcom/data/items.js
@@ -300,6 +300,9 @@ Zotero.Items = new function() {
 			if (this.isPrimaryField(field)) {
 				primaryFields.push(field);
 			}
+			else if (field == 'itemType') {
+				primaryFields.push('itemTypeID');
+			}
 			else {
 				fieldIDs.push(Zotero.ItemFields.getID(field));
 				if (Zotero.ItemFields.isBaseField(field)) {