Build Identifier: https://hg.mozilla.org/mozilla-central/rev/5ce3882eec21be3a70e4afc050959ca2f76bfa76 Mozilla/5.0 (Windows NT 10.0; WOW64; rv:53.0) Gecko/20100101 Firefox/53.0 ID:20170115030210 The problem is noticeable on long page. Over scrolling when mouse down on scrollbar. It is not intuitive behavior. Disabled smooth scroll fix the problem. Reproducible: always Steps To Reproduce: 1. Open long page (e.g., https://developer.mozilla.org/en-US/docs/Web/Events ) 2. Mouse down and keep on the empty area of vertical scrollbar and do not move mouse pointer 3. wait to stop scroll --- observe page scroll position, and thumb position 4. Mouse up and click (also do not move mouse pointer) --- observe page scroll position, and thumb position Actual Results: Page is over scrolling. The thumb is overshoot beyond position the mouse pointer. After Step4, scroll position of page is going back. Expected Results: Page should not be over scrolling. (Edge and Chrome does). After Step4, scroll position of page should not be going back. Regression window: https://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?fromchange=ec4622e6e1fa&tochange=4ef03db1385b Regressed by: Bug 957445
Maybe the same underlying issue as in bug 1328053?
Indeed, this may be the same root cause. I am adding a patch to Bug 1328053, which may fix this as well. Once Bug 1328053 lands, please re-test to see if it is fully fixed.
I have pushed a series of try builds out for the proposed fix to Bug 1328053. Hopefully we can use these builds to verify that it fixes this bug also.
I've reproduced this (Windows 10, FF Nightly). It appears the fix to Bug 1328053 does not correct it.
Still reproducible, but I think this is edge-case enough that I'm calling it fix-optional for 52. That said, we still have time to take a low-risk fix for 52 if you have more time to look into this, Kip :)
(In reply to Ryan VanderMeulen [:RyanVM] from comment #5) > Still reproducible, but I think this is edge-case enough that I'm calling it > fix-optional for 52. That said, we still have time to take a low-risk fix > for 52 if you have more time to look into this, Kip :) I won't likely have time to investigate this one before the trains run, but would be glad to take a look for the following release. I'll take the bug for now, but please feel free to steal this from me if anyone wants to get it in for 52.
Too late for a fix for 53, fix-optional for 54, minor carryover regression.