Firefox 50 is showing old "View autosave" dialog

[mar1in]

Using Wordpress 4.6.1. Works in Chrome. Only works from time to time in Firefox:

Steps to reproduce:

1. Create new post
2. Publish post
3. Modify content and wait for autosaving
4. Reload page

Expected result: Restore backup notice including restore backup button
Actual result: Autosave notice

After I debugged a little bit, I realized that Firefox is not able to delete the cookie 'wp-saving-post' by using wpCookies.remove('wp-saving-post'). It seems to work only when you specify the path: wpCookies.remove('wp-saving-post', '/app/wp-admin')

[mar1in]

Actual Result

[mar1in]

Expected result

[ramonopoly]

I can replicate this issue in Firefox 62 on WordPress v5.0-alpha-20181001.162241

Adding a path to wpCookies.remove does remove the cookie and allows subsequent checks for post data in localstorage, for example:

wpCookies.remove( 'wp-saving-post', '/wp-admin' ); 

at
https://core.trac.wordpress.org/browser/trunk/src/js/_enqueues/wp/autosave.js#L458

We'd probably want to provide a path when setting the cookie, for example userSettings.url, so we can use that same path when removing.

[Presskopp]

Firefox 112 was just released and I assume this is historic.