"Set Product Image" Bug since WP 3.9 Upgrade

Hi,

After upgrading to WP 3.9 the “Set product image” in product edit page does not open a popup like before (Here: http://s14.postimg.org/ov13x0k35/error4.png ), instead it opens a new page with WP media uploader (Here: http://s28.postimg.org/hyb5e74zx/error3.png )

I can eventually manage to add a product image but the browser isn’t redirected to the product page.

Strangely, the ‘Add product gallery images” works fine.

I’ve searched and noticed others have had this problem but cant find a fix;

http://wordpress.org/support/topic/set-product-image-no-popup

Thanks.

https://wordpress.org/plugins/woocommerce/