New UI doesn't handle connector javascript form checking properly

When a connector has javascript that checks for Configuration form legality via the checkConfig() method, switching tabs causes the UI to get confused. Sequence to reproduce:

(1) Create or edit a connector configuration with a checkConfig() method
(2) Click on a tab that has some checking
(3) Modify a field so that it is illegal
(4) Click on another tab

• The proper error message is indeed displayed
• The user clicks "OK" to cancel the alert
• The proper tab continues to be displayed
• The selected tab changes, and it should not

If you then click "Save", you will be incorrectly told that there is another connection of the same name.

You can try this easily by creating a SharePoint connection, going to the Server tab, and supplying a non-integer for the port number. Then click on the Throttling tab and see what happens.