Orizontal Windows bar appear with CSS3 Mega Menu ON

Joomla 3.5.1
JUX CSS3 Mega menu: 1.0.6
mysql: 5.5.49-37.9
php: 5.5.36
Browser: Firefox 47.0.1

template: Joomla51 Classic
template width: 1080 px
The screen resolution is 1280x800

Il you look at the bottom of the screen (see attachment menu-on.jpg) there is an horizontal bar.
If I unpublish JUX CSS3 Mega menu (see attachment menu off) the bar go off.

Is it possible to fix this problem?

Many thanks and regards

ATTACHEMENTS
menu-on.jpg
drive.google.com/file/d/0B-4cStHdZTSielp...b00/view?usp=sharing
menu-off.jpg
drive.google.com/file/d/0B-4cStHdZTSib04...Rzg/view?usp=sharing

Hi Osar.
Thank you for using our product.
Please give me link your site and your account of administrator via email: This email address is being protected from spambots. You need JavaScript enabled to view it.
I will check it for you soon.
Because I can't check the cause if don't have your site.
Hope You can empathy for me.

Hi Oscar,
Thanks your message,
I'm sorry. I checked your site on my computer with firefox browser and chrome browser.
But I don't see the horizontal bar in bottom.
Please view image
imgur.com/rWxOOC5
imgur.com/j32O0vE
Best Regards,
Huyen Tran

Hi Huyen,
did you check with a smaller windows size? On my syste the bar appears starting form 1572 px as in the accached picture.
drive.google.com/file/d/0B-4cStHdZTSiUWl...Z2M/view?usp=sharing
Thanks

Hi Oscar.
I'm sorry. I can't access your backend with your account that give for me.
Please check it again.

Hi Huyen,
try to access again now
Sorry

Hi Oscar.
Please check your site and feedback to me again.

Hi Huyen,
now seems to be OK. Good Job!!!
Can you explain to me what parameters you change? Just to avoid to disturb you again if I will change something in the future.
Many thanks and regards

Hi Oscar.
Thanks your feedback to me again.
1.I add some line code in the advanced tab below:
.wrapper960, .backgrounds .content_background{
width:100%!important;
}
Because You put megamenu module in the position that you has set the width and will shows horizontal bar ..
2. You can help me, write a review good and vote 100 point for each section for my product on JED:
extensions.joomla.org/extension/joomla-css3-mega-menu
Thanks your review.

In any case is it possible to have the template boxed again?
The solution that you find coud be ok for the home page but not for the other 3 template stypes the needs to be boxed
Thnks