Created attachment 356313 [details] Screenshot Sidebar menus are no longer rendered on GitLab. Not sure if this is a WebKit regression or if something changed in GitLab. Screenshot attached.
This bug is caused by accelerated compositing mode. Works fine with AC mode disabled.
Bisected down to r238583, which is the same regression behind bug #192307. Marking as a duplicate of that. https://trac.webkit.org/changeset/238583/webkit *** This bug has been marked as a duplicate of bug 192307 ***
*** This bug has been marked as a duplicate of bug 192597 ***