What Sticky Keys Actually Does: Visual Breakdown of Every Modifier State
Sticky Keys is not a blunt, binary switch. It runs an intelligent internal state engine that alternates between two distinct behavioral phases: the "latched" state and the "locked" state. Recognizing the difference between these two states explains why your keyboard occasionally types unexpected symbols or opens nested shortcut menus when the feature is active.
When you press a modifier key once under Sticky Keys, you activate the latched state. The system records that the modifier is active, but it only applies that modifier to the very next non-modifier key you strike. Once that subsequent key is pressed, the operating system registers the chord and immediately releases the modifier key back to an idle state. If you tap Shift once and then tap the letter "a", the screen outputs a capital "A", and the Shift key immediately turns off. The next letter you strike will be lowercase.
If you tap that same modifier key twice in rapid succession, you engage the locked state. This functions identically to Caps Lock, but applies to any modifier on the board. Double-tapping the Control key keeps Control active indefinitely. Every subsequent letter you hit acts as a shortcut: tapping "c" copies, tapping "v" pastes, and tapping "z" undoes previous actions. The locked state remains active across dozens of keystrokes until you hit the modifier key a third time to clear the buffer.
