Steps to reproduce: 1) Open macOS System Preferences to General pane 2) Show scroll bars: Always 3) Open safari to https://webkit.org 4) Open web inspector 5) Select Elements tab 6) Select any DOM node 7) Resize the DOM tree area See the attached screenshots. The DOM nodes themselves seem to respect Show scroll bars: Always, but the "= $0" variable becomes hidden behind the scroll bar.
Created attachment 455424 [details] Screenshot: variable partially hidden
Created attachment 455425 [details] Screenshot: variable shown
Created attachment 455426 [details] Screenshot: variable hidden
Also occurs without always-on scrollbars if you resize Web Inspector until `= $0` doesn't fit on the first line anymore, but the rest of the content does. Use of `position: absolute;` for this text seems suspicious, but changing that leads to a weird issue with the height of the blue "selected item" area until I move my cursor over it and back off of it. Need to reduce that issue to understand if it is in WebInspectorUI, or an underlying layout/repaint issue.
<rdar://problem/90662184>