The transparent background in menus has been plaguing me for some time now. The release of IE8 was my only hope for a fix. No luck there though as I am still seeing it on many JA sites.
If you see something like this then I have a way for you to overcome it.
most of the templates use a file called trans-bg-png to make the background of the moomenu. You will usually find it in the root of the templates images directory. If you open this file in an image editor you will find it is 1px by 1px in size. Resize it to 10px by 10px then save and upload over the old one. This fixes the issue in IE.
I hope the DEVs see this post because it would be good to maybe overcome it in future templates.
I have no idea why it occurrs for some people and not others but once I had 3 clients see the same thing so I decided I had to find a way to correct it.
I have seen in JA_Uvite it uses 3 of these images trans-bg.png, trans-1bg.png, trans-2bg.png so there may be more than just one.
I have also seen it reside in JA modules like JA_tabs where it is embeded in the plugin’s folder eg. “/plugins/content/ja_tabs/themes/uvite/trans-bg.png”.
Please add a reply to this post if it helps you.