The characters ' and " break the sidebar in preview mode if entered into the editor field

[amypink]

After updating to 4.6, if we enter the characters ' or " (as in hyperlinks) into the editor field (disabled visual editor), save, and preview the post, the recent posts widget in our sidebar shows the wrong thumbnail(s). Only the featured image of the current post is shown. If we just type "This is a test" into the editor, the recent posts thumbnails are normal.

[swissspidy]

Hey there,

Thanks for opening this ticket and welcome to WordPress trac!

This issue already popped up yesterday and we have a fix ready in #37697. It will be included in WordPress 4.6.1.

Just so you know, this has nothing to do with typing specific characters in the editor. That bug occurs when previewing a post that has a thumbnail, no matter what content it has. It doesn't happen anywhere else, only during preview.

[amypink]

Oh, I'm sorry for opening a duplicate ticket. Just for your information, the bug seems to disappear as long as you only enter normal letters and dots, as you can see in the screenshot.

Thanks and keep up the great work!

Best, Marcel

[jbenton]

At least from my experience with the other ticket, what determined whether or not the thumbnail issue occurred was whether or not a preview_nonce was triggered in the preview URL, not any particular characters. That brought along a _thumbnail_id in the URL as well, and that's what screwed up the thumbnails. So, for instance, a quick preview right after a new post was created (or sometimes saved as a draft?) wouldn't do it.