"Select All Earlier Measurements" Arrow Missing

I have been using VPhot frequently since I began a couple months ago.  One feature that has never worked on either Firefox or Chrome is the right arrow that enables the user to select all earlier measurements.  The attached screen grab shows the appearance in my browsers.  Highlighted with a red circle are the missing right-pointing arrows, both next to the checkboxes and at the top of the page.

Does anybody know why it appears this way in both of my browsers?  Thanks.

Tom