diff --git a/addons/web/static/src/css/base.css b/addons/web/static/src/css/base.css
index 6b334f10c15..07861d4e6e8 100644
--- a/addons/web/static/src/css/base.css
+++ b/addons/web/static/src/css/base.css
@@ -347,3 +347,32 @@
   width: 100%;
   white-space: nowrap;
 }
+.openerp2 .oe_form_group_cell {
+  position: relative;
+}
+.openerp2 .oe_form_group_cell .oe_field_char, .openerp2 .oe_form_group_cell .oe_form_field_selection select {
+  width: 99%;
+}
+.openerp2 .oe_form_group_cell .oe_form_field_selection select {
+  min-width: 90px;
+}
+.openerp2 .oe_layout_debugging .oe_form_group {
+  border: 1px solid red;
+}
+.openerp2 .oe_layout_debugging .oe_form_group_cell {
+  border: 1px solid blue;
+  padding-bottom: 1em;
+}
+.openerp2 .oe_layout_debugging .oe_layout_debug_cell {
+  position: absolute;
+  color: white;
+  bottom: 0;
+  left: 0;
+  background: green;
+}
+.openerp2 .oe_layout_debugging .oe_layout_debug_cell {
+  display: block;
+}
+.openerp2 .oe_layout_debug_cell {
+  display: none;
+}
diff --git a/addons/web/static/src/css/base.sass b/addons/web/static/src/css/base.sass
index fe9408c18a1..746bc5d32b4 100644
--- a/addons/web/static/src/css/base.sass
+++ b/addons/web/static/src/css/base.sass
@@ -340,6 +340,28 @@ $colour4: #8a89ba
         .oe_form_button
             width: 100%
             white-space: nowrap
+    .oe_form_group_cell
+        position: relative
+        .oe_field_char, .oe_form_field_selection select
+            width: 99%
+        .oe_form_field_selection select
+            min-width: 90px
+    .oe_layout_debugging
+        .oe_form_group
+            border: 1px solid red
+        .oe_form_group_cell
+            border: 1px solid blue
+            padding-bottom: 1em
+        .oe_layout_debug_cell
+            position: absolute
+            color: white
+            bottom: 0
+            left: 0
+            background: green
+        .oe_layout_debug_cell
+            display: block
+    .oe_layout_debug_cell
+        display: none
     // }}}
 
     .openerp
diff --git a/addons/web/static/src/js/view_form.js b/addons/web/static/src/js/view_form.js
index a7684712d1f..c03d75f59f8 100644
--- a/addons/web/static/src/js/view_form.js
+++ b/addons/web/static/src/js/view_form.js
@@ -758,6 +758,17 @@ openerp.web.FormRenderingEngine = openerp.web.Widget.extend({
                 w.replace($elem);
             }
         });
+        $('<button>Debug layout</button>').appendTo(this.$element).click(this.do_toggle_layout_debugging);
+    },
+    do_toggle_layout_debugging: function() {
+        if (!this.$element.has('.oe_layout_debug_cell:first').length) {
+            this.$element.find('.oe_form_group_cell').each(function() {
+                var $span = $('<span class="oe_layout_debug_cell"/>').text($(this).attr('width'));
+                $span.prependTo($(this));
+            });
+        }
+        this.$element.toggleClass('oe_layout_debugging');
+
     },
     process_any: function($tag) {
         var self = this;
@@ -858,6 +869,7 @@ openerp.web.FormRenderingEngine = openerp.web.Widget.extend({
         // Now compute width of cells
         $table.find('tbody > tr').each(function() {
             var to_compute = [],
+                row_cols = cols,
                 total = 100;
             $(this).children().each(function() {
                 var $td = $(this),
@@ -867,13 +879,13 @@ openerp.web.FormRenderingEngine = openerp.web.Widget.extend({
                         if ($child.attr('orientation') === 'vertical') {
                             $td.addClass('oe_vertical_separator').attr('width', '1');
                             $td.empty();
-                            cols--;
+                            row_cols--;
                         }
                         break;
                     case 'label':
                         if ($child.attr('for')) {
                             $td.attr('width', '1%');
-                            cols--;
+                            row_cols--;
                             total--;
                         }
                         break;
@@ -881,7 +893,7 @@ openerp.web.FormRenderingEngine = openerp.web.Widget.extend({
                         to_compute.push($td);
                 }
             });
-            var unit = Math.floor(total / cols);
+            var unit = Math.floor(total / row_cols);
             _.each(to_compute, function($td, i) {
                 var width = parseInt($td.attr('colspan'), 10) * unit;
                 $td.attr('width', ((i == to_compute.length - 1) ? total : width) + '%');
diff --git a/addons/web/static/src/xml/base.xml b/addons/web/static/src/xml/base.xml
index 069f48fb48e..3f5e067285c 100644
--- a/addons/web/static/src/xml/base.xml
+++ b/addons/web/static/src/xml/base.xml
@@ -948,7 +948,7 @@
             <input t-att-type="widget.password ? 'password' : 'text'"
                 t-att-name="widget.name"
                 t-att-id="widget.id_for_label"
-                t-attf-class="field_#{widget.type} #{_(['integer', 'float', 'float_time']).contains(widget.type) ? 'oe-number' : ''}"
+                t-attf-class="oe_field_#{widget.type} #{_(['integer', 'float', 'float_time']).contains(widget.type) ? 'oe-number' : ''}"
             /><img class="oe_field_translate oe_input_icon" t-if="widget.field.translate" t-att-src='_s + "/web/static/src/img/icons/terp-translate.png"' width="16" height="16" border="0"/>
         </div>
     </t>