Editing a view drops old view if syntax error.
Droping old view and creating a new one should be an atomic operation.
Thank you for the report, I've fixed it in Git. You can download the "Current development version" from http://www.adminer.org/#download
This is still broken in 3.6.4 as far as I'm concerned.
If I click alter view, it's empty.
You seem to have CSS turned off.
Please don't fill out this field.
Altering views in MySQL terminates transaction. Adminer tries to recreate the original view if creating the new one fails. If even the original view couldn't be created then there's not much to do.
Another solution would be to try to create the new view before dropping the old one with some temporary name and if it passes then drop the temporary view, drop the old one and create the new one with the correct name.