Iām using Chrome under Kubuntu Linux with a KDE desktop, although Iām sure other browsers, operating systems and keyboard layouts might be affected. When using a Swedish keyboard layout, the ? character is produced by pressing shift-+ where + is the key to the right of num row 0. However, ctrl-shift-+ is hijacked by the browser as zoom in and consequently the cheatsheet is not toggled.
This came up as I was going through the getting started list. This may be a wontfix in terms of providing a different keyboard shortcut. However it might be worth pointing out in the getting started list that the cheatsheet is the same as āshortcuts & formattingā in the hamburger menu as a fallback.