Nm - seems to work on the CDN version - may be something in the fixed .js
Fix from issue #5382 removes the rounded corners from the dialog C, but the popup E retains the rounded dialogs.
There seems to be a cascaded effect here.
Found the fix, don't know how to commit it.
.first() is a filter and as such needs to be removed before the rest of the chained actions.
I fixed the original issue on branch master (pre 1.3) and applied the same fix on branch 1.2-stable for the 1.2.1 release. Because we changed the way we apply corner styling for 1.3 the code on 1.2-stable is a bit different and I missed that I had to add another .end() there. Thanks a lot!
Closing as fixed by 113e3b4