I just found a solution to a problem that was driving me crazy for months, and I'm passing it along now for my fellow sufferers. Firefox was blocking popups in Google Reader, even though I explicitly told Reader to allow popups for the entire domain Google.com. Turns out this isn't a bug (as the programmer joke goes), it's a feature. Read on for the fix.First, I'll describe the problem. I use Google Reader to view hundreds of articles every day, collected from dozens of Web sites. I use the keyboard to navigate: Space bar to move from one item to the next, and the V key to open an article on the original site. That V key gets a good workout; many sites, like InformationWeek, only put excerpts in the RSS feed, and you have to go to the original site to read the entire article.

Firefox's normal behavior is to block popups. However, it's easy enough to whitelist domains where you want popups to appear, like Google.com.

Months ago, I noticed a bug: After I'd been using Google Reader for more than a half-hour or so in any individual session, Firefox started blocking popups on the site. I checked to see if I'd configured my whitelist correctly, and I had. Firefox was supposed to be allowing popups from Google, but it was blocking them. Re-starting the browser fixed the problem, but that was inconvenient, and it only fixed the problem for a while -- it would recur after another half-hour or so.

Turns out that's a design feature of Firefox. A person signing himself Graham, the Google Reader Guide, explains:

Apparently there's a limit on the number of popups that a site can have, even if you've designated it as an "allowed" site for popups in Firefox. So if you are using the "v" key for dozens of articles in Reader, you might hit that limit. Restarting the browser resets the count. But if, like me, you run into this limit a lot, you can actually change it:

1. In a Firefox window, enter "about:config" in the address bar.
2. In the "Filter" field, type "popup_maximum".
3. One preference, called "popup_maximum" appears; double-click the "value" number.
4. Enter a new, appropriately large value. I used 2000, just to be on the safe side.

Now Firefox will give any "allowed" sites even more free rein with popups and you should be able to "v" away happily without interruption.

I tried the fix and it works! Thanks, Graham! Hopefully, if you've been having the same annoying problem, this fix will work for you, too.