@cedric.chenavier@a-mano.fr, there is no "blog" option in "https://dev.amano.io/0iehiyOM", can you provide other steps to reproduce issue.

Sorry ! 
We played a lot with it.
I just reset the blog feature on the dev webapp: https://dev.amano.io/0iehiyOM

Since my post, we tried a stock S7 Edge with same OS and Chrome version.
No problem at all.

We tried many operations to pinpoint a possible "source" of the problem.
Eventually, on the faulty S7, the only way to solve it, was to re-init chrome setting (purge all user pref).
Install/re-Install Chrome did not change anything.
It seeems, something in the user account was inducing the problem. We were unable to pinpoint precisely what.
Problems still remained in canary though.

Hope it rings a bell.

Cheers, 

Cedric

1) Bisect Range: https://chromium.googlesource.com/chromium/src/+log/56.0.2909.0..56.0.2910.0?pretty=fuller&n=10000
2) Bisect script pointed to:  https://chromium.googlesource.com/chromium/src/+/7f8de7508a3e8098ed174c59daa5b068808382f8

@bokan, can you please look into this,thanks

This is an intentional change described here:

Intent to ship: https://groups.google.com/a/chromium.org/forum/#!searchin/blink-dev/Top$20Controls%7Csort:relevance/blink-dev/BK0oHURgmJ4/PZqveT2LBAAJ

Description and rationale: https://github.com/bokand/URLBarSizing

The reason for the "dead-zone" is that the scroller is an element on the page, rather than the viewport. When the bar hides, we don't resize the page (and thus the element) any longer.

Depending on how prevalent this is, I'm inclined to close this as WontFix. The page already suffers from UX issues because of this in stable - scrolling doesn't show/hide the url bar so I suspect this pattern isn't terribly common. I'll have to try it in Safari which has the same behavior, though I suspect it'll "appear correct" is because they lock the URL bar to be shown when there's no viewport scrolling. We could do the same but I'd prefer to avoid that unless we end up breaking lots of sites.

The correct fix would be for the page to set the <md-content> element which is the scrolling container to have `overflow: visible` so that the viewport is responsible for scrolling. Making this change removes the dead-zone and enables scrolling to show/hide the URL bar.

I'm going to leave this open for now to keep the issue in mind but I'm removing the stable-blocker label since this is intentional.

This change shipped to stable in M56 a week or two ago without much issue so we're not going to make any big changes here.