Hovering over a button and then moving the mouse away makes the tooltip disappear. Clicking the button persists the tooltip until the user clicks something else.

This is because tooltips persist on elements that are in focus.

Tooltip persistence on focus is a desirable behavior for keyboard navigation, but it's often undesirable for mouse users. The user already knows what they just clicked, so after clicking the button, the tooltip should go away again on mouseout.

A possible way of implementing this is to persist tooltips if an element is :focus-visible and not just :focus.