NoScript Icon Dropdown is, can be, decidedly Laggy before the site list displays.
Quite often the "menu bar" displays, then a very noticeable delay, then the sites populate.
(I noted this on https://www.msn.com/en-us/autos/. Didn't check, particularly, if it's observable "everywhere".)
NoScript Icon Dropdown Laggy
NoScript Icon Dropdown Laggy
Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.1.19) Gecko/20110420 SeaMonkey/2.0.14 Pinball NoScript FlashGot AdblockPlus
Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:52.0) Gecko/20100101 Firefox/52.0 SeaMonkey/2.49.5