Substitute character actions than the last one can also be undone by pressing multiple times. was one of a handful of keyboard sequences chosen by the program designers at Xerox PARC to control text editing. Presumably these particular keystrokes were chosen because of their location on a standard QWERTY keyboard, since the Z (undo), X (cut), C (copy), and V (paste) keys are located together at the left end of the bottom row of the standard QWERTY keyboard. Substitute character A substitute character (␚) is a control character that is used in the place of a character that is recognized to be
Keyboard layout the letter Ґ, which does not exist in Russian. The other long-standing problem was the omission of the apostrophe, which is used in Ukrainian almost as commonly as in English (though with a different value), but which also does not exist in Russian. Both of these problems were resolved with the "improved Ukrainian" keyboard layout for Windows available with Vista and subsequent Windows versions. There also exists an adapted keyboard for Westerners learning Ukrainian (mostly in the diaspora) which closely matches the qwerty keyboard, so that the letters either have the same sound or same shape, for example pressing the