This is _very_ wierd, is cross-platform (it happens on OS X, Linux and Windows), and happens in FF2, FF 3.0.X and FF 3.X. So far I'm only able to reproduce it at https://bugzilla.mozilla.org, so it may have something to do with bugzilla (or with a particular version or server-setup of bugzilla). 1) Visit https://bugzilla.mozilla.org. Keep this window/tab open. You don't need to be logged in. The window can be minimized or in the background. The tab containing containing https://bugzilla.mozilla.org needn't be the current tab (the one currently visible in its window). 2) Choose Tools : Clear Private Data, select only "Authenticated Sessions" and click on "Clear Private Data Now". 3) In any currently open tab/window that doesn't currently contain https://bugzilla.mozilla.org, try to visit that site. Notice that nothing happens. On OS X, you can make this problem stop happening by doing any of the following: A) Click on the Desktop (to put Firefox into the background) and then on one of the Firefox windows (to put it back into the foreground). or B) Click on the location bar twice (not a double-click), so that a flashing text-entry cursor appears. Then press Return. or C) Open a new window and try visiting https://bugzilla.mozilla.org in that window. None of these (A, B or C) work on Windows and Linux. That they work on even one platform suggest this may be at least partially a focus bug.
Component: Layout → Location Bar and Autocomplete
Product: Core → Firefox
QA Contact: layout → location.bar
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