diff --git a/addons/web/static/src/js/views/graph/graph_controller.js b/addons/web/static/src/js/views/graph/graph_controller.js
index 2953b99f731..1c580a25bd6 100644
--- a/addons/web/static/src/js/views/graph/graph_controller.js
+++ b/addons/web/static/src/js/views/graph/graph_controller.js
@@ -177,7 +177,7 @@ var GraphController = AbstractController.extend(GroupByMenuMixin,{
             .find('.o_graph_button[data-mode="stack"]')
             .data('stacked', state.stacked)
             .toggleClass('active', state.stacked)
-            .toggleClass('o_hidden', state.mode !== 'bar' || !this.renderer.isStackable);
+            .toggleClass('o_hidden', state.mode !== 'bar');
         _.each(this.$measureList.find('.dropdown-item'), function (item) {
             var $item = $(item);
             $item.toggleClass('selected', $item.data('field') === state.measure);
diff --git a/addons/web/static/src/js/views/graph/graph_renderer.js b/addons/web/static/src/js/views/graph/graph_renderer.js
index e24de02879c..6cb2c023d0e 100644
--- a/addons/web/static/src/js/views/graph/graph_renderer.js
+++ b/addons/web/static/src/js/views/graph/graph_renderer.js
@@ -71,8 +71,6 @@ return AbstractRenderer.extend({
 
         this.chart = null;
         this.chartId = _.uniqueId('chart');
-        // the bar charts are considered stackable a priori
-        this.isStackable = true;
         this.$legendTooltip = null;
         this.$tooltip = null;
     },
@@ -782,34 +780,9 @@ return AbstractRenderer.extend({
         // prepare data
         var data = this._prepareData(dataPoints);
 
-        // The datapoints (with non zero value) can be grouped by
-        // their originIndex and associated labels.
-        // If at least one group formed in that way has two elements
-        // this.isStackable will be true.
-        var groupMemberCounts = data.labels.map(function () {
-            return {};
-        });
-        this.isStackable = false;
-        for (var i = 0; i < data.datasets.length; i++) {
-            var dataset = data.datasets[i];
-            var originIndex = dataset.originIndex;
-            if (this.isStackable) {
-                break;
-            }
-            for (var j = 0; j < dataset.data.length; j++) {
-                if (dataset.data[j]) {
-                    if (originIndex in groupMemberCounts[j]) {
-                        this.isStackable = true;
-                        break;
-                    } else {
-                        groupMemberCounts[j][originIndex] = 1;
-                    }
-                }
-            }
-        }
         data.datasets.forEach(function (dataset, index) {
             // used when stacked
-            dataset.stack = self.isStackable && self.state.stacked ? self.state.origins[dataset.originIndex] : undefined;
+            dataset.stack = self.state.stacked ? self.state.origins[dataset.originIndex] : undefined;
             // set dataset color
             var color = self._getColor(index);
             dataset.backgroundColor = color;
diff --git a/addons/web/static/tests/views/graph_tests.js b/addons/web/static/tests/views/graph_tests.js
index 7cbab784829..d44d2e61a81 100644
--- a/addons/web/static/tests/views/graph_tests.js
+++ b/addons/web/static/tests/views/graph_tests.js
@@ -133,7 +133,7 @@ QUnit.module('Views', {
                 data: [3,5],
                 label: "Count",
                 originIndex: 0,
-                stack: undefined,
+                stack: "",
             }
         );
         assert.checkLegend(graph, 'Count');