Steps to reproduce: 1. Get a debug build. 2. Start NightlyDebug 3. Press Command+n to open a second window. 4. Close the first window. 5. Wait for a while (for GC/CC to happen) or go to about:memory and press "minimize memory usage". 6. Press Command+q to quit Firefox. Expected result: A line in the terminal showing a DOMWINDOW for browser.xul has been destroyed (like "--DOMWINDOW == 12 (0x114ca84b8) [serial = 3] [outer = 0x0] [url = chrome://browser/content/browser.xul]") after step 5, and another similar line after step 6. Actual result: Both windows are destroyed at shutdown. This bug may exist only on Mac (the only platform where I tested this). I don't know if this is caused by Firefox's front end or by something in the platform, so I didn't really know in which component to file this bug.

sounds similar to bug 850456

(In reply to Andrew McCreight [:mccr8] from comment #1) > sounds similar to bug 850456 Agreed :-) (That bug "detects" the leak with an add-on, whereas this bug uses the console log of a debug build.) Make them dependent ftb.