Scroll Handler

[sb8244]

Firstly: thanks so much for an awesome set of components! These are really great.

I recently ran into a problem with position: fixed elements and the Trigger alignment. When using fixed, it will separate from the element and stay behind on the page. I noticed that window resizing fixed this and traced the effect down to this library.

Would you consider a PR that adds a scroll handler to this library? I feel that this could potentially end up having downstream effects on rc-trigger and other libraries that use it. It could potentially hook into the existing startMonitorWindowResize and monitorBufferTime properties.

Thanks!

[ccqgithub]

https://github.com/react-component/align/pull/126/files
This is my local solution.