IE 10 appending unselectable=on

I am working on a website.

In the UI, a dropdown menu is not working. Using the Dev tools, came to know that IE 10 is somehow appending "unselectable=on" for the <div> which contains the dropdown menu.

The code does not have anywhere unselectable attribute set to "on".

Hence I tried to override using CSS and javascript but no help.

Any suggestions would be helpful

Thanks

Ankit