diff --git a/js/tabularfieldsselector.js b/js/tabularfieldsselector.js
index f97d443adb..8a2077eace 100644
--- a/js/tabularfieldsselector.js
+++ b/js/tabularfieldsselector.js
@@ -384,7 +384,7 @@ $(function()
 		_flatten_fields: function(aFields)
 		{
 			// Update the "flattened" via of the fields
-			this.aFieldsByCode = [];
+			this.aFieldsByCode = {}; // Must be an object since indexes are non-numeric
 			for(var k in aFields)
 			{
 				for(var i in aFields[k])
@@ -515,4 +515,4 @@ $(function()
 			});
 		}
 	});	
-});
\ No newline at end of file
+});