We don’t actually support custom CSS on this forum, we’d love to but we’d quickly go out of business!
If you do find an answer please do share it here so that others can use it, we’ll set you up with a coupon for your efforts! If anyone else in the community happens to know the answer, we’d love it if you could also post your solutions (theres a coupon for that too!)
If you are having problems with canvas after updating you will need to post a ticket to WooCommerce for further support. We normally advise that you take a backup before updating so please accept my apology on Nick’s behalf on this one.
We are also releasing v2.2.10 of Page Builder tomorrow which addresses a number of small bugs so this may also help you.