I believe that the current behavior of the quick Notes button is in my experience slightly unexpected, I expected it to either open a popover, or a new window but rather it replaced the current tab, when I found out that it does that I instead choose to Hold Command then click it thinking that maybe that would open it in a new tab, but nothing happened?
To me that was just slightly unexpected and having it be a popover rather than a direct link would help or even if it opens in a new tab.