Explorer 7 visualitzacion problem with mod_cpsearc

The dropdown menu of the mod_cpsearch with the default CSS is working ok in FF, and IE9.
We have problems with the IE7 and the mod_cpsearch dropdown menu that is not showing correctly, have you some idea where is the problem? We see that the drowpdown menu is under the other selections and cannot see correctly.

We attach and images of the problem.





Thank you.

To the best of our knowledge mod_cpsearch works fine even with the venerable IE7.
Try for yourself:
demo1720.solidsystem.it/