What does the "Close Bmk" switch do ?

[Potjoe-97]

Hi,

First, thank you very much for this great hack.
I tried to find what the "Close Bmk" switch do, but after looking in the issues, the repo, and on the web, I was not able to find the answer. Could you help me figure it out ?

Thank you

[ddvk]

i think the bookmarks stay open when you navigate to pages