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Chrome is the only important desktop browser born without menus and that's probably the reason why web apps can override shortcuts like Alt+F. It's important to point out that you can use shortcuts like Alt+F and Alt+E to open Chrome's wrench, but not in Google Spreadsheets.
While Chrome's interface was so great that many other browsers used it as an inspiration, Google Docs continues to use the old-school menus from Microsoft Office 2000.