The flickering effect can be seen more rapidly by resizing the width of your browser window while viewing the fiddle, or by dragging the vertical handler that is between the javascript and output.

Able to reproduce the issue on Win-10 using chrome reported version #61.0.3163.91 and latest canary #63.0.3218.0. Observed flickering of scrollbar upon clicking -1/+1 buttons.

But in M52, in which the issue doesn't exist as per the reporter in comment #0, the scrollbar doesn't seems to show up upon clicking -1/+1 buttons.(as per attached screen cast 765680@M52.mp4).

imdashizmono@ - Could you please let us know the expected behavior and the behavior in M52 or please provide any other url to test the issue from TE-end. This will help us in triaging the issue further.

Thanks...!!

Deleted: 765680@M52.mp4 421 KB

	765680@M52.mp4 421 KB View Download

Well, in version 52 the scrollbar stays hidden until you see the orange box touch the bottom of it's container.

Please read the new explanation, then check the updated link (-5/+5 added, along with a width display):
https://fiddle.jshell.net/mvhj726s/7/

The issue that is occurring is caused by a section of width values that make the image large enough to require a scrollbar, BUT creating the scrollbar lessons the available width, thus shrinking the image to where the scrollbar is NOT required.

The width where this occurs is between 197 and 213 px.

Chrome 53+ gets confused, and every other check that is made causes it to toggle the scrollbar. The logic seems to be something like: 

-Size of image without scrollbar is too large, so enable scrollbar.
-Reflow occurs, making image smaller.
-Size of image with scrollbar is small enough to fit, so disable scrollbar.
-Reflow occurs, making image larger.


(Note: My apologies, should've specified that Chrome v52 just worked differently, and just doesn't examine the same flickering issue. It still functions strangely)

For Chrome 52, there is a different bug around the same situation. The setup behaves like this:

-Setting width below 197 px, scrollbar is disabled and the image size is based on the width value.

-Setting width above 213 px, scrollbar is enabled and the image size is based on the width value MINUS the scrollbar width.

-Setting width between 197-213:
 -If previous width was below 197, scrollbar is disabled, but the image size is based on the width value MINUS the scrollbar width. Functions this way until a value outside the threshold is set.
 -If previous width was above 213, scrollbar is enabled, but the image size is based on the width value (not taking scrollbar into account).


I feel that the expected behavior should behave like this:

-Setting width below 197px, scrollbar disabled.
-Setting width at or above 197px, scrollbar enabled.


Does this help give a better understanding?

Thank you for providing more feedback. Adding requester "krajshree@chromium.org" to the cc list and removing "Needs-Feedback" label.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

Tested the issue on Win-10 using chrome version #52.0.2709.0 by navigating to URL: https://fiddle.jshell.net/mvhj726s/7/
Observed that the grey layout in the scrollbar at 210px goes up a little and at 205px it goes down again on pressing the "-5" button.
Plz refer the attached screen cast for reference.

imdashizmono@ - Could you please verify the screen cast and please let us know if it is the expected behaviour for M52 chrome version.
This will help us in bisecting the issue further.

Thanks...!!

Deleted: 765680.mp4 1.0 MB

	765680.mp4 1.0 MB View Download

The screen cast is showing the expected behavior for M52.

Thank you for providing more feedback. Adding requester "krajshree@chromium.org" to the cc list and removing "Needs-Feedback" label.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

Looks like it might be a layout issue.

Over to skobes for further triage.

None of the test cases are available anymore. Unable to reproduce.