This has been reported from Adrian Cid Almaguer.
On Ubuntu 14.04, the dialog box to select the hat to wear is not properly shown.
On Firefox 39.0.3, hats are not visible, and Firebug console shows the following error.
On Google Chrome 44.0.2403.89, they are visible, but when the user tries to select the hat to wear, he sees the following.
I cannot reproduce it on OS X 10.12, using either Firefox 42.0 or Google Chrome 47.0.2526.80.