The latest mockup is: https://bug744906.bugzilla.mozilla.org/attachment.cgi?id=614521
Created attachment 635688 [details] screenshot work in progress
Created attachment 635745 [details] [diff] [review] v1 not test on linux and windows yet, but should be ok.
Comment on attachment 636262 [details] [diff] [review] v1.1 This patch includes 4 icons (in tools-icons-small.png). The debugger icon is not yet finished. So I used the WebConsole icon as a placeholder. This will be fixed in bug 760446.