Component: IconButton tooltip persists when button becomes disabled

[aduth]

Issue Overview

Mouse events that the Tooltip relies upon for determining when to show and hide a tooltip are not fired for disabled nodes. As a result of the implementation in #2405, it was decided that it is fine for tooltips not to be shown for these disabled elements. However, where this becomes an issue is when a button becomes disabled while a tooltip is already visible, where the tooltip is then permanently stuck on screen because the mouseleave event will not be fired to dismiss the tooltip.

Steps to Reproduce (for bugs)

1. Navigate to Posts > Add New
2. Using mouse, press the Undo button until button is disabled
   • Related: Undo level present on load #2916
3. Move mouse away from Undo button

Expected Behavior

Tooltip should be dismissed.

Current Behavior

Tooltip is stuck.

Possible Solution

The tooltip assumes a single child, in this case the button element. We could check for changes to the disabled prop, but it's not guaranteed that DOM attribute is exclusively dependent on a prop by this name.

A more extreme approach might be to attach a MutationObserver to find when the disabled DOM attribute is applied to the tooltip child.