diff --git a/lib/web/mage/adminhtml/wysiwyg/tiny_mce/tinymce4Adapter.js b/lib/web/mage/adminhtml/wysiwyg/tiny_mce/tinymce4Adapter.js
index 9779be85133f8..92737d56462fd 100644
--- a/lib/web/mage/adminhtml/wysiwyg/tiny_mce/tinymce4Adapter.js
+++ b/lib/web/mage/adminhtml/wysiwyg/tiny_mce/tinymce4Adapter.js
@@ -645,9 +645,9 @@ define([
 
                 // process tag attributes string
                 attributesString = attributesString.gsub(/([a-z0-9\-\_]+)="(.*?)(\{\{.+?\}\})(.*?)"/i, function (m) {
-                    decodedDirectiveString = encodeURIComponent(Base64.mageEncode(m[3].replace(/"/g, '"')));
+                    decodedDirectiveString = encodeURIComponent(Base64.mageEncode(m[3].replace(/"/g, '"') + m[4]));
 
-                    return m[1] + '="' + m[2] + this.makeDirectiveUrl(decodedDirectiveString) + m[4] + '"';
+                    return m[1] + '="' + m[2] + this.makeDirectiveUrl(decodedDirectiveString) + '"';
                 }.bind(this));
 
                 return '<' + match[1] + attributesString + '>';