cua-enable-cua-keyscua-enable-cua-keys is a variable defined in `
cua-base.el'. Its value is
tDocumentation: Enable using C-z, C-x, C-c, and C-v for undo, cut, copy, and paste. If the value is t, these mappings are always enabled. If the value is `shift', these keys are only enabled if the last region was marked with a shifted movement key. If the value is nil, these keys are never enabled. You can customize this variable.