Widgets editing screen don't handle expired nonces gracefully

[dd32]

The Widgets screen doesn't handle an expired nonce gracefully, and can result in the user thinking something saved, when in actual fact it was silently discarded.

For example

• Adding/Removing Widgets appears to work, doesn't take effect
• Editing a Text Widget (or any titles of other widgets) and hitting save will result in a spinner, and then disappear the same way a successful save operates, even though the ajax calls returned -1 to signify a nonce error / not logged in error

[dd32]

The easiest way to trigger this scenario is to run jQuery( '#_wpnonce_widgets' ).val('123456') in the console.

[DrewAPicture]

@dd32: Is this new to trunk or something older?

[dd32]

Haven't tested, but I assume it's been around since we first added the current generation widgets screen that uses ajax.

[iseulde]

Related: #24447.