eddiesutton

Fixed it! At least, fixed it for my custom child theme built on the Twenty Thirteen theme. Here’s what I found

Found the culprit on line 912 inside the styles.css file (not inside the ‘css’ directory). Note that, for me, the nefarious style is the clip-path. I created a style to override that inside my child theme and it’s working. The change from prior versions of ’twenty thirteen’ is from a style for ‘clip’ and changing that to a style for ‘clip-path’. That killed my sub-menu behavior. In more detail, the complete old style looks like:

clip: rect(1px, 1px, 1px, 1px);

…and this was replaced with:

clip-path: inset(50%);

So I created a style in my child theme that goes like:

clip-path: none;

That fixed it. 

Even so, this was incredibly annoying and time-consuming and that was a bunch of hours for which I will not be compensated. So I guess that’s part of my contribution to the world of ‘open source’. 

Hope this helps someone else.