From T113163:
After an error occurs when you try to submit the "save page" dialog, a red message appears. When I dismiss that message, the "Save page" button in the dialog box remains grayed out. The only way to try again is to leave the "save page "dialog and reopen it.
After an error occurs when you try to submit the "save page" dialog, a red message appears. When I dismiss that message, the "Save page" button in the dialog box remains grayed out. The only way to try again is to leave the "save page "dialog and reopen it.
This is intentional; it's for "unrecoverable" errors, which MediaWiki defines as things that won't get better if you just try again. "The page is protected" is one of these; "You failed the CAPTCHA" is not.
Is that good UI behaviour though? It's mighty confusing to be able to dismiss the error, but then to be unable to try clicking "save page" again.
I assume VE currently considers Parsoid 400s as "unrecoverable" errors. If so, I think the UI definitely needs some more explanation and guidance for users here. "Something went wrong" is nowhere near enough.