Users wishing to schedule a patch for deployment via the deployment calendar page must edit a large wikitext table on the calendar page. I, personally, have had trouble editing this table with visualeditor.
My current method of adding a patch for deployment is to edit the source of the page; find in page searching for the date I want to deploy; add my patch; and squinting very hard before clicking "Preview". Sometimes, despite my very hard squinting, I break the table and have to cancel and start over.
User:Krinkle made a new page format that is more compatible with visualeditor. This is what it looks like to add a patch to the Morning Backport and Config window using this new page format: