diff --git a/lib/editor/tinymce/tiny_mce/3.3.9.2/plugins/moodlemedia/js/media.js b/lib/editor/tinymce/tiny_mce/3.3.9.2/plugins
index f79a787..93dc1e5 100644
--- a/lib/editor/tinymce/tiny_mce/3.3.9.2/plugins/moodlemedia/js/media.js
+++ b/lib/editor/tinymce/tiny_mce/3.3.9.2/plugins/moodlemedia/js/media.js
@@ -153,6 +153,7 @@ function generatePreview(c) {
     pl.id = !pl.id ? 'moodlemediaid' : pl.id;
     pl.name = !pl.name ? 'moodlemedianame' : pl.name;
     pl.align = !pl.align ? '' : pl.align;
+    pl.wmode = 'opaque';
 
     // Avoid annoying warning about insecure items
     if (!tinymce.isIE || document.location.protocol != 'https:') {