@agable are you able to reproduce this as well, or are you simply passing along the report?

If I Cmd-T and close quickly, I think I am clicking to close before the button actually animates into place, so I'm actually clicking on nothing.

But in the video, it seems like once the reporters are in this state, they can't ever click the close button until they move the tab around in the tabstrip.  That I cannot reproduce, and I'm looking to clarify whether that is actually happening or not.

Yeah, that's definitely what is happening -- the initial click immediately after the tab is created puts something into a bad state so that the button doesn't respond to further clicks until it is reinitialized.

I'm just passing this on -- I don't have a MacOS machine, and this doesn't seem to reproduce on my Ubuntu or ChromeOS boxes.

I can kinda-sorta reproduce this. What happens for me:

1) Create a new tab
2) Very quickly click where the close button is, before it animates in
3) Keep clicking the close button relatively quickly

None of those clicks are delivered to the close button until I pause clicking or until I move the mouse, so I'm guessing that they are being delivered to the underlying tabstrip as a succession of double clicks and so on.

Note that Safari suffers from the same problem: if you try to click a tab's X as it is animating in, clicks are not delivered until you wait a bit or move the mouse. As such, I suspect this is a Cocoa design behavior around animated elements, or else a Cocoa bug. I am not sure what we would do about this.

However, I cannot reproduce the behavior in the video at all, nor understand how it could happen in theory.

rohitrao@, do you have any idea how we could get into this state?

 Issue 649066  has been merged into this issue.

We have some weird code that runs a nested run loop if you click on a tab. Theoretically, clicking on the close button should get around this, but I bet if you click during the animation, we end up running that nested run loop until you move the mouse or something.

https://cs.chromium.org/chromium/src/chrome/browser/ui/cocoa/tabs/tab_strip_drag_controller.mm?q=maybeStartDrag:&sq=package:chromium&dr=C&l=96

Here's a similar example where it gets stuck in rapid closure mode.

Deleted: Untitled.mov 1.4 MB

Untitled.mov 1.4 MB Download

I can reproduce the bugs in comments #3 and #7.  I still cannot reproduce the bug in the original report.

For #3, it's definitely related to double-clicks.  If I space my clicks further apart, eventually one of them gets recognized as a click on the close button.  If I go into the system settings and lower my double-click speed, I have to space them even further apart to get the tab to close.

For #7, I can repro but haven't looked at the code yet.  Definitely seems like it's stuck in rapid closure mode.

 Issue 662153  has been merged into this issue.

This Mac quality of life bug haven't been touched by its owner in a while, so I'm bumping it back to "available". Feel free to change it back to "assigned" if you'd rather not have someone else take it.

***Mass UI Triage***

Able to repro the issue on the latest canary 72.0.3618.0 on Mac OS 10.13.6. Opened multiple(20/30) new tabs using Cmd+T and tried closing by clicking on the close button and there were no action on some clicks when trying to close the new tabs clicking on the close button.