UserAgent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/55.0.2868.3 Safari/537.36

Steps to reproduce the problem:
1. Bookmark the same page twice in multiple bookmark folders
2. Click on the blue star

What is the expected behavior?
The blue star menu would notice that the bookmark is multiply listed.

Or, maybe, that attempting to add the same site twice would cause an error

What went wrong?
It only showed a single entry.

Did this work before? No 

Chrome version: 55.0.2868.3  Channel: n/a
OS Version: 
Flash Version: Shockwave Flash 23.0 r0

The bookmark manager, and especially the star on the right end of the address bar, should be aware of a page being bookmarked more than once.