There are two types of shortcuts: those handled by OS and those handled by Chrome

• Alt-Tab is an example of a native shortcut
• Shift-Left is an example of Chrome-handled shortcut

Puppeteer doesn't emulate native shortcuts because native shortcuts depend on the active window, which is out of control for puppeteer.

Certain shortcuts, such as "select all", are handled differently on different platforms:

• On Win and Linux, Ctrl-A is handled by Chrome, and puppeteer does emulate this
• On OS X, ⌘-A is handled by OS X, and puppeteer doesn't emulate this