fields: the key for tooltip is "description"

dream/platform/src/number_field/numberfield.js

@@ -13,7 +13,8 @@
       var input = this.element.querySelector('input');
       input.setAttribute('value', options.value);
       input.setAttribute('name', options.key);
-      input.setAttribute('title', options.title || options.key);
+      input.setAttribute('title',
+        options.property_definition.description);
     })
 
     .declareMethod('getContent', function () {

dream/platform/src/string_field/stringfield.js

@@ -13,7 +13,8 @@
       var input = this.element.querySelector('input');
       input.setAttribute('value', options.value || "");
       input.setAttribute('name', options.key);
-      input.setAttribute('title', options.title || options.key);
+      input.setAttribute('title',
+        options.property_definition.description);
     })
 
     .declareMethod('getContent', function () {