Another tab is already working on this.

Helloooo!

I continuously get the message "another tab is already working on this" while trying to edit any of my pages. This error began when I tried to install a reservation button with my reservation system Xola. I followed Xolas installation guide of COPY + PASTE THIS CODE INTO YOUR SITE'S COMMON HEADER OR FOOTER : <script type="text/javascript"> (function() { var co=document.createElement("script"); co.type="text/javascript"; co.async=true; co.src="https://xola.com/checkout.js"; var s=document.getElementsByTagName("script")[0]; s.parentNode.insertBefore(co, s); })(); </script>
after that I was unable to follow the second step of pasting the button code in the needed spot as any code from the dragable code element would limbo in "loading", and I continuously got the message "another tab is already working on this". I have since deleted the code, turned off the xola plug in, updated everything, cleared my browser cache, and rebooted my PC, yet I still get the repeating message of "another tab is already working on this". Please help!

Thank you,
Jimmy