StickyKeys operates in two modes: key latching mode and key locking mode. Tapping ONCE on a modifier key causes it to go into LATCHED mode. If you have the sound features of StickyKeys enabled, a short low beep - high beep will be heard. As soon as the next non-modifier key is pressed the modifier key(s) will be released. Tapping TWICE in succession on a modifier key will put it into LOCKED mode. If you have the sound features of StickyKeys enabled, you will hear a short low - high beep after the first tap and a single high beep after the second tap. Once a modifier key is LOCKED, it will stay "locked down" until that modifier key is hit a third time. Any and all of the modifier keys (SHIFT, CTRL, and ALT) can be latched or locked in combination.
For shared or public use computers, there is an optional "Turn off when pressing Two keys at once" feature to keep non-disabled users from being confused if StickyKeys is accidentally left on. Whenever an able-bodied typist uses a keyboard, they will hold the modifier key down and strike another key simultaneously. If the "Turn off when pressing Two keys at once" shutoff feature is enabled, StickyKeys will detect that two keys are down simultaneously and automatically turn the StickyKeys feature off.
Some people do not like to have keyboard sounds while others find them useful. The ability to turn the different feedback sounds on or off is provided in the StickyKeys dialog box under the "Adjust" menu. Also, it is possible to disable the LOCKED mode of StickyKeys described above if it is not desired.
On United States keyboards or when using "United States" as your country and keyboard layout, StickyKeys treats the modifier keys as identical pairs. In other words, StickyKeys will treat the left and right shift (SHIFT), the left and right control (CTRL), and the left and right alternate (ALT) keys the same. Treating the modifier keys as identical pairs allows the user greater flexibility. For example, if the user entered LOCKED mode by tapping the left shift key twice, they could perform their intended function and exit LOCKED mode by tapping the right shift key once, since the two modifier keys are treated the same.
On non United States keyboards or when not using "United States" as your country or keyboard layout, you may find that your particular international keyboard attempts to distinguish between the left and right modifier keys. In particular, your international keyboard may need to distinguish between the left and right alternate (ALT) keys. This is typically done by giving the right alternate key a new name, instead of just "Alt", it is now called the "AltGr" key. "AltGr" is an abbreviation for "alt-graphics". For international keyboard layouts, StickyKeys will still allow the user to move freely between the left and right shift (SHIFT) or control (CTRL) keys, but you will notice a difference in the behavior of the left and right alternate (ALT) keys. The left alternate key will behave as the standard "Alt" key, typically used to quickly access a menu item, while the right alternate key will behave as the "AltGr" key, which many international keyboards use to access special characters important to their individual languages. Both the "Alt" and the "AltGr" keys can still be used in either LATCHED or LOCKED mode.