Refactor `highlight-tooltip` implementation to use zero timeout
This is a follow-on issue to !38478 (merged).
See details in this thread: !38478 (comment 291813016)
Description
Refactor logic in highlight-tooltip.js
to use window.setTimeout(showTooltip, 0)
to get around problem of the selection still existing when mouseup (click) event happens, even though it will be going away due to the click.
Currently there's complex logic to deal with this, the timeout 0 approach may be cleaner and more elegant.