Andd I have none of those gray or black boxes here eithre. But I have had similar experiences at other sites. I sus[pect it may result from visual resources depleting. When it happens to me, I log off the enternet totally, including closing the browser. And after a few moments of waiting I reload the browser and log back on. This has alays worked fopr me. Once or twice I have had to reboot the whole machine. If none of that works, I recommend you try screaming, blind, panic.