diff --git a/addons/mass_mailing/static/src/js/wysiwyg.js b/addons/mass_mailing/static/src/js/wysiwyg.js
index fdaad692501..b856d5af9cd 100644
--- a/addons/mass_mailing/static/src/js/wysiwyg.js
+++ b/addons/mass_mailing/static/src/js/wysiwyg.js
@@ -5,6 +5,25 @@ var Wysiwyg = require('web_editor.wysiwyg');
 var MassMailingSnippetsMenu = require('mass_mailing.snippets.editor');
 
 const MassMailingWysiwyg = Wysiwyg.extend({
+    //--------------------------------------------------------------------------
+    // Public
+    //--------------------------------------------------------------------------
+
+    start: async function () {
+        const res = await this._super(...arguments);
+        // Prevent selection change outside of snippets.
+        this.$editable.on('mousedown', e => {
+            if ($(e.target).is('.o_editable:empty') || e.target.querySelector('.o_editable')) {
+                e.preventDefault();
+            }
+        });
+        return res;
+    },
+
+    //--------------------------------------------------------------------------
+    // Private
+    //--------------------------------------------------------------------------
+
     /**
      * @override
      */