It's ok for me in 53.0.2785.143 m - but I'm running Windows 10.
I'm looking forward to moving away from the Flash uploader on the site, so as soon as there is a way out of it I'll be making the jump
.
If the problem doesn't go away, you can go to the preferences page on the site and disable the flash uploader ("Use the Flash-based uploader to upload attachments"):
https://www.electronicspoint.com/account/preferences
However, that will mean you can't upload multiple files in one go.