diff --git a/addons/point_of_sale/static/src/js/gui.js b/addons/point_of_sale/static/src/js/gui.js
index 11da0b4441f..365a27b1cc6 100644
--- a/addons/point_of_sale/static/src/js/gui.js
+++ b/addons/point_of_sale/static/src/js/gui.js
@@ -335,7 +335,8 @@ var Gui = core.Class.extend({
         this.chrome.loading_message(_t('Closing ...'));
 
         this.pos.push_order().then(function(){
-            window.location = '/web' + ((session.debug)? '?debug' : '') + '#action=point_of_sale.action_client_pos_menu';
+            var url = "/web#action=point_of_sale.action_client_pos_menu";
+            window.location = session.debug ? $.param.querystring(url, {debug: session.debug}) : url;
         });
     },
 
diff --git a/addons/web/static/src/js/action_manager.js b/addons/web/static/src/js/action_manager.js
index 8d33f1ab4ac..ebf2429d2ab 100644
--- a/addons/web/static/src/js/action_manager.js
+++ b/addons/web/static/src/js/action_manager.js
@@ -835,7 +835,7 @@ var ActionManager = Widget.extend({
     ir_actions_act_url: function (action) {
         var url = action.url;
         if (session.debug && url && url.length && url[0] === '/') {
-            url = $.param.querystring(url, 'debug');
+            url = $.param.querystring(url, {debug: session.debug});
         }
 
         if (action.target === 'self') {
diff --git a/addons/web/static/src/js/apps.js b/addons/web/static/src/js/apps.js
index 5dd5b576fc4..520fb3210c4 100644
--- a/addons/web/static/src/js/apps.js
+++ b/addons/web/static/src/js/apps.js
@@ -155,8 +155,11 @@ var Apps = Widget.extend({
         self.get_client().then(function(client) {
             self.client = client;
 
-            var qs = (session.debug ? 'debug&' : '') + 'db=' + client.dbname;
-            var u = client.origin + '/apps/embed/client?' + qs;
+            var qs = {db: client.dbname};
+            if (session.debug) {
+                qs.debug = session.debug;
+            }
+            var u = $.param.querystring(client.origin + "/apps/embed/client", qs);
             var css = {width: '100%', height: '400px'};
             self.$ifr = $('<iframe>').attr('src', u);
 
diff --git a/addons/web/static/src/js/framework/session.js b/addons/web/static/src/js/framework/session.js
index 2e643637052..fa83bf79044 100644
--- a/addons/web/static/src/js/framework/session.js
+++ b/addons/web/static/src/js/framework/session.js
@@ -32,7 +32,8 @@ var Session = core.Class.extend(mixins.EventDispatcherMixin, {
         this.avoid_recursion = false;
         this.use_cors = options.use_cors || false;
         this.setup(origin);
-        this.debug = ($.deparam($.param.querystring()).debug !== undefined);
+        var debug_param = $.deparam($.param.querystring()).debug;
+        this.debug = (debug_param !== undefined ? debug_param || 1 : false);
 
         // for historic reasons, the session requires a name to properly work
         // (see the methods get_cookie and set_cookie).  We should perhaps
diff --git a/addons/website/static/src/js/website.theme.js b/addons/website/static/src/js/website.theme.js
index 6b4fd81c7ae..2db3d1c0e5d 100644
--- a/addons/website/static/src/js/website.theme.js
+++ b/addons/website/static/src/js/website.theme.js
@@ -127,7 +127,7 @@ var Theme = Widget.extend({
         }
         this.$el.addClass('loading');
 
-        if (!reload && !session.debug) {
+        if (!reload && session.debug !== "assets") {
             var self = this;
             return ajax.jsonRpc('/website/theme_customize', 'call', {
                 enable: enable,