Mozilla/5.0 (Macintosh; U; Intel Mac OS X; en-US; rv:1.8.1.3) Gecko/20070309 Firefox/2.0.0.3 Similar to bug 387913. On Mac, the resizing event doesn't fire until you mouse up or you pause resizing and then continue. Steps to reproduce: 1. Run the script in the URL field 2. Resize the window smoothly. Expected results: Alert as soon as you start resizing. Actual results: Alert only moves when you release the mouse button or you momentarily pause resizing with the mouse button still down and then continue.

Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.5; en-US; rv:1.9.0.5) Gecko/2008120121 Firefox/3.0.5 Encountering the same issue. This is problematic for JavaScript-based page layout as it makes the UI appear sluggish.

I see the same problem on Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.0.5) Gecko/2008122103 Gentoo Firefox/3.0.5. Problem appears to be fixed on Mozilla/5.0 (X11; U; Linux i686 (x86_64); en-US; rv:1.9.1b2) Gecko/20081201 Firefox/3.1b2 Have you tried the beta or the latest nightly? http://releases.mozilla.org/pub/mozilla.org/firefox/releases/3.1b2/ http://ftp.mozilla.org/pub/mozilla.org/firefox/nightly/latest-trunk/

Firefox 3.1 beta 2 (Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.5; en-US; rv:1.9.1b2) Gecko/20081201 Firefox/3.1b2) does fire the event before the mouse button is released, but the frequency of firing the event is still quite slow and causes pretty bad visual repaint lag. By comparison, Safari on the same box fires the event faster than I can perceive and thus repaint speed is nice.

This is partly duplicate of bug 114649 and partly duplicate of bug 460620.

Sorry, wrong bug.