in the left menu, if you click on the "Scripts" button above the AGO button some images are loaded via http instead of https.

specifcally, I get warnings for these links:

gf1.geo.gfsrv.net/cdn63/10e31cd5234445e4084558ea3506ea.gif
gf1.geo.gfsrv.net/cdn9e/4f73643e86a952be4aed7fdd61805a.gif
gf1.geo.gfsrv.net/cdn30/aa3e8edec0a2681915b3c9c6795e6f.gif