Steps: 1. Inspect <body> on this Bugzilla page. 2. Add new rule by clicking the plus button at the bottom of the styles sidebar. 3. Click on the "Inspector Style Sheet:0" link. Expected: "Inspector Style Sheet" resource opens with the newly added CSS rule in it. Actual: Resources tab opens with some other resource selected. "Inspector Style Sheet" isn't present in the left sidebar.
<rdar://problem/37807676>
*** This bug has been marked as a duplicate of bug 188819 ***