Does the scrollbar show up while scrolling, or does it not show up at all?

Definitely not a P1.

OK, I looked at this. I don't think it is cros specific. It may only show with a smallish browser window though (i.e. small enough to need to scroll the content).

The reason this doesn't show a scrollbar as near as I can tell is that the dialog content is not contained in a scrolling div, it is all in the 'body' div.

I'm not sure whether hiding the scrollbar for the dialog body is intentional?

We could fix this in a couple of ways, assuming we want to (it does seem confusing):
a) Fix this specific dialog by wrapping the checkboxes in a scrolling div.
b) Modify our dialog styling to show a scrollbar if the content scrolls.

'a' would be simplest and is the solution I am leaning towards.
'b' is more general but may not be desired everywhere and I'm not entirely sure how to go about it.

+scottchen who tweaked some dialog overflow behavior recently.

@stevenjb: I can still scroll the dialog body, even if the scrollbar is not visible. To me this seems like a blink bug (being able to scroll, but scrollbar is not visible).

Sounds like it? I'm not really that familiar with <dialog> or <cr-dialog> to be honest.

So I did a bisect which revealed https://chromium.googlesource.com/chromium/src/+log/c61e0b14d96fcb5c4592d2c12551994f879e5490..1c02ea390c65d2292b64ffbb57c4a4d4873c34b4.

The related revision seems to be r475210. Still does not explain why the scrollbar shows fine on other platforms though.

@stevenjb: Assigning to Scott for further investigation, given the bisect findings. Have you actually started working on this? (bug is marked as Started).

If this is a blink bug on CrOS, a minimal repro would be helpful.

Definitely looks like a Blink bug, since I discovered that removing the box-shadow at [1], fixes the problem.


[1] https://cs.chromium.org/chromium/src/ui/webui/resources/cr_elements/cr_dialog/cr_dialog.html?q=cr_dialog.html&sq=package:chromium&dr&l=16, 

Uploading a screencast, to help Blink team reproduce.

Deleted: scrollbar_missing.mp4 959 KB

	scrollbar_missing.mp4 959 KB View Download

Turning on layers on the devtools, reveals that something layer-related is going wrong, attaching new screencast. Notice how the scrollbar layer seems to be incorrectly positioned when the box-shadow is turned on.

Deleted: layers_issue.mp4 1.4 MB

	layers_issue.mp4 1.4 MB View Download

Could you bisect to what broke the behavior before
https://chromium.googlesource.com/chromium/src/+log/c61e0b14d96fcb5c4592d2c12551994f879e5490..1c02ea390c65d2292b64ffbb57c4a4d4873c34b4
happened to expose it?

Tried to go further back with bisect-builds, but I am getting constantly the following crash, so was not able to get any valueable info.

[13098:13098:0630/181635.162601:ERROR:resource_bundle.cc(767)] Failed to load /tmp/bisect_tmpWFPwzq/chrome-linux/keyboard_resources.pak
Some features may not be available.
Received signal 11 SEGV_MAPERR 000000000000
#0 0x55627667af27 base::debug::StackTrace::StackTrace()
#1 0x55627667aa9f base::debug::(anonymous namespace)::StackDumpSignalHandler()
#2 0x7efc0a3bf330 <unknown>
#3 0x556276b4c783 base::GetHourClockType()
#4 0x556278144ed3 ash::SystemTrayController::SystemTrayController()
#5 0x55627816bb39 ash::WmShell::WmShell()
#6 0x5562781986a1 ash::WmShellAura::WmShellAura()
#7 0x55627817ef4c ash::Shell::CreateInstance()
#8 0x5562784ed26e chrome::OpenAsh()
#9 0x556278361398 ChromeBrowserMainExtraPartsAsh::PreProfileInit()
#10 0x55627634f37a libva info: VA-API version 0.35.0
libva info: va_getDriverName() returns 0
libva info: Trying to open /usr/lib/x86_64-linux-gnu/dri/nvidia_drv_video.so
libva info: va_openDriver() returns -1
ChromeBrowserMainParts::PreProfileInit()
#11 0x55627635020e ChromeBrowserMainPartsLinux::PreProfileInit()
#12 0x556275ec565c chromeos::ChromeBrowserMainPartsChromeos::PreProfileInit()
#13 0x55627634e5e2 ChromeBrowserMainParts::PreMainMessageLoopRunImpl()
#14 0x55627634df01 ChromeBrowserMainParts::PreMainMessageLoopRun()
#15 0x556275ec52cf chromeos::ChromeBrowserMainPartsChromeos::PreMainMessageLoopRun()
#16 0x5562750775e5 content::BrowserMainLoop::PreMainMessageLoopRun()
#17 0x556275344a46 content::StartupTaskRunner::RunAllTasksNow()
#18 0x55627507579b content::BrowserMainLoop::CreateStartupTasks()
#19 0x55627507ad0c content::BrowserMainRunnerImpl::Initialize()
#20 0x556275072f18 content::BrowserMain()
#21 0x5562762ef4cc content::ContentMainRunnerImpl::Run()
#22 0x5562762ee0b0 content::ContentMain()
#23 0x556274c09b50 ChromeMain
#24 0x7efc05867f45 __libc_start_main
#25 0x556274c099b1 <unknown>
  r8: 0000000000000000  r9: 000000000000007f r10: 000007041c923c00 r11: 0000000000000004
 r12: 00007fff25081248 r13: 000007041c709400 r14: 000007041c97e6e0 r15: 000007041c973400
  di: 000007041c6a62c0  si: 000007041c6f1180  bp: 0000000000000000  bx: 0000000000000000
  dx: 00000000000006f1  ax: 000055627c223148  cx: 0000000000000001  sp: 00007fff25080de0
  ip: 0000556276b4c783 efl: 0000000000010206 cgf: 0000000000000033 erf: 0000000000000004
 trp: 000000000000000e msk: 0000000000000000 cr2: 0000000000000000
[end of stack trace]
Calling _exit(1). Core file will not be generated.

Any updates here? Can someone from the Blink side pick up this bug? Per comment#14 findings, this is a bug somewhere within Blink.

+bokan, chaopeng who have been working on overlay scrollbars for Chrome OS

Looks like the scrollbar layer is being positioned to the box-shadow rather than the border box. szager@, have you had a chance to look?

This is becoming a rather hot topic on CBC. We are duping most posts to this one
https://productforums.google.com/forum/#!topic/chromebook-central/X2bEGL5dqxU

#CBC-RS/TC-watchlist

Re #21, this issue is tracking an actual _bug_ where a scrollbar should show up but doesn't. This isn't about the change to make scrollbars overlay and animated. 

For users who really don't like the new behavior, we can use issue 761237

#22 - issues reported on CBS actually include some _missing_ scrollbar reports, but they are mixed in with the _complaints_

Missing scrollbars have been reported - but it is not clear if this is because of a website design issue or this bug.

It has been challenging to sort the bugs from the complaints.

I have edited the thread to reference the _complaint_ tracking report and will attempt to isolate the actual _missing_ experiences.

Thanks

(Bulk Edit) Adding the new conops Chrome OS hotlist to all open issues with the "#CBC-RS/TC-watchlist" tag, our former tracking tag.