nsIDOMWindowInternal.focus() fails for "stacked" modal windows (it should bring the top-most window to the front and activate it). The error console shows: Error: uncaught exception: [Exception... "Component returned failure code: 0x80004005 (NS_ERROR_FAILURE) [nsIDOMWindowInternal.focus]" nsresult: "0x80004005 (NS_ERROR_FAILURE)" location: "JS frame :: chrome://browser/content/utilityOverlay.js :: openPreferences :: line 340" data: no] Steps to reproduce: 1) Open two browser windows in Firefox. 2) In one of the Windows, choose "Tools | Options" to open the preferences dialog. Then open a modal sub-dialog, e.g., by clicking the "Colors..." button on the Content preferences tab. 3) Click on the 2nd browser window and choose "Tools | Options" from the menu. Expected result: the sub-dialog (e.g., the "Colors" window) should be brought to the front and activated. Instead, nothing happens. This problem occurs on Windows XP and Mac OS X (both running the Firefox 2.0 official release -- build 20061010). This is confusing, especially if the window you are trying to re-activate is behind another window. The same error occurs if you open an extension's modal preferences window from the Add-ons window.

So I don't get this js error when I have the patch from bug 348357 applied, although nothing happens afterwards. You're probably right, the existing sub-dialog should be brought up front.

i can confirm this bug with Mozilla/5.0 (Macintosh; U; Intel Mac OS X; en-US; rv:1.8.1.7pre) Gecko/2007090107 BonEcho/2.0.0.7pre When i go to the Prefs -> Advanced -> Update -> Show Update History and i minimize the windows with the Update History open and reopen the Prefs again i get : Error: uncaught exception: [Exception... "Component returned failure code: 0x80004005 (NS_ERROR_FAILURE) [nsIDOMWindowInternal.focus]" nsresult: "0x80004005 (NS_ERROR_FAILURE)" location: "JS frame :: chrome://browser/content/utilityOverlay.js :: openPreferences :: line 350" data: no] I was only able to reproduce this on mac

Yeah, the patch from bug 348357 fixed that error, but this bug isn't fixed. To get this fixed, see bug 348357, comment 10: " However, I was thinking about removing that piece of code completely, to be able to fix bug 360686, but I guess that might indeed regress the cached compose bug. " It might break things, though.