I'm working on a Windows 7 computer that uses AOL webmail.
Suddenly, opening messages in their own windows is flaky. Often the windows are all blank inside.
This is worst on Internet Explorer (11) but is also somewhat an issue with Google Chrome.
I have turned off the popup blocker and sometimes see better results. And, I've toggled it.
AOL webmail has a setting to NOT show the mail in a separate window. This way it works for READING.
But, writing opens a new window anyway and can be either blank or it won't show details like the line header "To:"
And, when this happens, writing the message body hides the To; and Subject: lines (unless you show the window full screen) and there is no SEND button anywhere....
Negative points for saying "don't use AOL mail". That's too obvious and not helpful :-)