If using Raindrop sidebar and left click on bookmark in it, it opens that bookmark but closes the sidebar. This is a bug.
If right click on a bookmark and select open in new tab then it doesn't close the side bar. This is how left click should work.
The standard Chrome Bookmarks in Sidebar work correct and doesn't close the sidebar when left clicking on a bookmark.
The raindrop sidebar in Firefox works correct and doesn't close the sidebar when left clicking on a bookmark in Raindrop sidebar.
To keep the product consistent the Chrome sidebar bookmark left click should be the same as the behavior left click of Chrome standard bookmark bar and Firefox raindrop bar.