`OverlayManager.js:65` should set the `showExtendedGridlines` option, not `showExtendedGridLines` (different casing).
Created attachment 420049 [details] Patch
Comment on attachment 420049 [details] Patch View in context: https://bugs.webkit.org/attachment.cgi?id=420049&action=review > Source/WebInspectorUI/ChangeLog:9 > + Replace all instances of "GridLines" (camelcase) with "Gridlines" > + to match the protocol naming. I feel like this should actually be the opposite. I think "GridLines" is more accurate here because you're drawing "lines for CSS grid contexts". Not to mention it would likely be a smaller/simpler patch :P Also, this shouldn't be problematic to update the protocol with a new name since we haven't included any of the grid related types/commands/events in any legacy protocols yet.
Created attachment 420058 [details] Patch
This patch modifies the inspector protocol. Please ensure that any frontend changes appropriately use feature checks for new protocol features.
Comment on attachment 420058 [details] Patch r=me
Committed r272768: <https://commits.webkit.org/r272768> All reviewed patches have been landed. Closing bug and clearing flags on attachment 420058 [details].
<rdar://problem/74260822>