diff --git a/addons/web_editor/static/src/js/wysiwyg/widgets/color_palette.js b/addons/web_editor/static/src/js/wysiwyg/widgets/color_palette.js
index 955faa039a9..54dc8232bb5 100644
--- a/addons/web_editor/static/src/js/wysiwyg/widgets/color_palette.js
+++ b/addons/web_editor/static/src/js/wysiwyg/widgets/color_palette.js
@@ -38,6 +38,7 @@ const ColorPaletteWidget = Widget.extend({
      */
     init: function (parent, options) {
         this._super.apply(this, arguments);
+        this.customColorsArray = [].concat(...customColors);
         this.style = window.getComputedStyle(document.documentElement);
         this.options = _.extend({
             selectedColor: false,
@@ -173,7 +174,7 @@ const ColorPaletteWidget = Widget.extend({
             return;
         }
         this.el.querySelectorAll('.o_custom_color').forEach(el => el.remove());
-        const existingColors = new Set(customColors.concat(
+        const existingColors = new Set(this.customColorsArray.concat(
             Object.keys(this.colorToColorNames)
         ));
         this.trigger_up('get_custom_colors', {