[IMP] add warning re. changed behavior of backbone which may be changed in the client

bzr revid: xmo@openerp.com-20131202151838-z26qnz0xpt3tigrd

addons/web/static/src/js/search.js

@@ -90,6 +90,10 @@ my.SearchQuery = B.Collection.extend({
             }
             B.Collection.prototype.add.call(this, model, options);
         }, this);
+        // warning: in backbone 1.0+ add is supposed to return the added models,
+        // but here toggle may delegate to add and return its value directly.
+        // return value of neither seems actually used but should be tested
+        // before change, probably
         return this;
     },
     toggle: function (value, options) {