Not certain why, but the issue resolved itself. It happened after I’d DELETED the lines you’d provided from the CSS. It should’ve worked before they were inserted, but who knows?
Sorry, this is obviously not caching issue. Not after a week of trying to get the Widgets menu to work properly on multiple browsers on different machines.
This worked for me! Then, later, after I removed/reinserted it (I was dealing with a problem of certain pages refusing to update)…it stopped working. Caches cleared, etc., but “Post It” still survives…