Since Firefox 157 and 158, the updated search history sidebar is much less responsive and laggy than in previous versions. I used to be able to go in, tab into the history list, and hold down delete to quickly remove large sections or use the arrow keys to navigate quickly. In the new version, holding down delete will remove about 1 page per second, and continue even after the key has been released. Aside from the visual aspects, the newer version performs and feels much worse than the previous. Not only are less results visible on the screen at once, the menu is also slower to navigate.
Unfortunate
