In plain English
Ever tried to move your mouse onto a tooltip and had it vanish before you got there? That’s the exact problem this rule fixes. Any extra content that pops up on hover or on keyboard focus, like tooltips, definition popovers, and mega-menus, has to behave:
- Dismissable: you can make it go away (usually with the Escape key) without moving your mouse or focus.
- Hoverable: you can move your pointer onto it and it stays open.
- Persistent: it doesn’t disappear on a timer; it stays until you dismiss it or move away.
Who this is for
- Screen-magnifier users, who must move across the screen to read a tooltip; if it vanishes on the way, they never see it.
- Keyboard users, who need a way to dismiss a popover that’s covering something.
- People who read slowly, for whom auto-hiding content disappears too soon.
What “good” looks like
Keep the extra content on screen and let people reach and dismiss it.
Hover a "?" help icon → tooltip appears
• Move the mouse onto the tooltip → it stays open ✓
• Press Escape → it closes ✓
• Do nothing → it stays put ✓Where stores get it wrong
Size-guide and help tooltips that close the instant the pointer leaves the trigger, mega-menus with no way to dismiss them by keyboard, and popovers that cover the content beneath with no escape. See the common failures list for how these show up in real stores.