Created attachment 633199 [details] [diff] [review] patch v1 nsBrowserAccess is (if I understood the code correctly) only used to open links with custom target attributes in a new window or new tab. We should continue to use about:blank as default here instead of about:newtab because that new docShell/window will be used to load a new link in it and there's no need to load about:newtab in there. While working on bug 753448 I noticed the following assertion: http://mxr.mozilla.org/mozilla-central/source/dom/base/nsGlobalWindow.cpp#1471 This happens because we're opening a new tab and will be loading about:newtab and thus swapping a preloaded page. So it's actually more a timing issue that we didn't hit this assertion so far, I think.
Comment on attachment 633199 [details] [diff] [review] patch v1 Good catch; the only caller that passes null that I could find was nsContentTreeOwner::ProvideWindow, which indeed really specifically wants about:blank.
Thanks for the quick review! https://hg.mozilla.org/integration/fx-team/rev/eaddef238d96