Just downloaded 10.5 with intention of upgrading my 9.5. So, while customizing it I noticed that if I hide the Menu toolbar, copy-paste by using the usual keyboard shortcuts (Ctrl+C -> Ctrl+V) is not working. I'm a minimalist freak, most of the controls are hidden and I am using extensively keyboard shortcuts. Nevertheless, these should be working no matter what.
Windows 8 x64 here.
Those hotkeys are provided by the menu commands themselves so if you turn off the menu you turn off the hotkeys.
You can add "pure" hotkeys that don't rely on menus or buttons through the Settings / Customize / Keys tab.
Then the OOtB configuration of DO is plain wrong 
Why would these operations depend on some UI ?! The standard keyboard shortcuts should work no matter what.
The OOtB configuration isn't wrong, because the menu is in the OOtB configuration. If you delete parts of the UI that have hotkeys attached, you delete the hotkeys as well and have to replace them if you want standalone hotkeys.
(Easier solution, move the unwanted menus into a submenu somewhere so they're still part of the toolbars but not taking up space.)
Anyway, following your advice solved my problem. Thanks 