Sidebar and vertical tabs won't show up

I am on version 155 of the browser, and the sidebar is not showing up for me. Clicking the sidebar toggle button also does nothing. I've tried going into settings and toggling the show sidebar option, but that also doesn't do anything, as if the sidebar feature doesn't exist. Toggling vertical tabs just makes the tab bar disappear, and I've tried both the options menu and right-clicking the side bar toggle button. Is there an error, or am I missing something?