This is with Firefox Nightly 36.0a1 (2014-11-13), on Mac OS X Yosemite (10.10). I attempted to download ftp://ftp.free.fr/mirrors/ftp.ubuntu.com/releases/13.10/ubuntu-13.10-server-armhf+omap4.img While the download was in progress, I am able to bring up the small downloads popup window (the down arrow button). But if I try to bring up the separate Downloads window via the menu item Tools..Downloads, firefox entirely locks up. Nothing is responsive. I end up force-quitting Nightly.app.
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