Created attachment 77226 [details] Repro page The initial problem is reproducible both on latest WebKit (r74228) and Chromium (10.0.620.0 (69946)), breakpoint setting behavior differs. Load the repro page in browser, open Inspector (or DevTools), switch to "Scripts" panel -- observe that scripts list is empty. Reload the page -- script will appear. Now, if you try to set a breakpoint on the script body, it is impossible in Chromium, and behaves strangely in Safari: breakpoint is set, but can't be removed by clicking on the gutter, until you close Inspector and open it again.
Safari bug is a duplicate of this one https://bugs.webkit.org/show_bug.cgi?id=51243, fixed in r74261.
Fixed by http://trac.webkit.org/changeset/77489.