Steps to replicate the issue (include links if applicable):

• You give multiple files to the first screen of the Upload Wizard on Commons
• You go on to the subsequent screen where you enter details of each file
• Validation finds a problem with one of them (say, a title which has already been used), so hides the "next" button
• You press "remove file" next to the problematic file

What happens?:

• The wizard does not restore the "submit" button
• You have to close the page because there's no way forwards, so you lose all the metadata you have for the other files

What should have happened instead?:

• Removing the file should have caused the page to re-validate

Other information (browser name/version, screenshots, etc.):

Browser: Firefox