Pages with meta refresh do not refresh unless window is focused

This may be a problem with this particular build, but I see a few people have the same problem.

I'm involved in a number of projects that have ongoing experiments. Data is presented as simple web pages, usually a table of numbers or graphs. These web pages get regenerated on the server periodically, mostly once or twice a minute. The head of these pages goes something like:

<title>some title</title> <meta content="60" http-equiv="Expires"> I usually have quite a few Firefox windows open, each pointing to a different project. That way I can glance at the screen and quickly see if anything is going wrong. A few revisions ago, this worked well. But after upgrading to 3.6.28, the windows stopped refreshing unless the window was focused (mouse pointer moved into the window). I have to drag the mouse to all the windows in order for them to refresh. Note that I open the web pages with a URL of "file://webpage.html" since the files are local. There is a web server that serves them, and if I open a page with "http://server/webpage.html", the refresh happens as expected. I tried restarting Firefox in save mode, and that does not help. And this only happens for me on Solaris/x86. Or at least version 18.0.1 on Windows XP seems to auto-refresh even if the page is opened with "file://...". I hate to upgrade, but I downloaded a copy of 18.0.1 for Solaris. The problem persists. Any ideas? Other than opening the pages as "http://..." which clogs up the logs of the otherwise lightly used web server and having the administrator yell at me?