[1] mouseenter and mouseleave events should not be composed (smaug著, ) <https://github.com/w3c/uievents/commit/6ddc097f8473c7e99fc100a7c3bda81dffce875f>
[2] mouseenter and mouseleave events should not be composed, issue #208 by smaug---- · Pull Request #210 · w3c/uievents () <https://github.com/w3c/uievents/pull/210>