Dear Steve,
since we had the same issue - indeed we saw that the click and scroll up issue is fixed in 56 beta.
But still there is a related issue. If one clicks in a tree on links which are not on the visible area, there is the scroll up behaviour too.
If one clicks on tree items being visible on load of page, the click action works - a popup shows up "Test on click outer child item"
Now, if you scroll down some items to a non visible tree item on page load, e.g. to item 40 and click on it, the page scrolls up instead of showing the popup.
For us it is important to have this behaviour working, since our apps in production currently are not working in Chrome 55 and use big tree views .
Please let me know if you need more information regarding this issue,
Thank you and best regards
Andreas