Closed Bug 1372289 Opened 7 years ago Closed 7 years ago

Nightly: Unclickable horizontal line across the top of some windows


(Firefox :: Tabbed Browser, defect, P1)

55 Branch



Firefox 56
56.1 - Jun 26
Tracking Status
firefox-esr52 --- unaffected
firefox54 --- unaffected
firefox55 --- unaffected
firefox56 --- fixed


(Reporter: caspy77, Assigned: Oriol)



(Keywords: regression, Whiteboard: [photon-visual])


(3 files)

I update Nightly daily and today after updating I noticed that some, but not all of my windows have a horizontal 2 pixel line across the top edge.

Tested in safe mode and the issue persisted. Another Nightly user on IRC, also on Windows 10, reported having the same thing (others did not).

The notably irritating issue here is that I keep my browser windows full screen and naturally push my mouse to the top of the screen to click on a tab, which no longer works. This has made selecting tabs a chore.
Thanks for reporting, Caspy7. Do you have a screenshot you can post?
Flags: needinfo?(caspy77)
Keywords: regression
Flags: needinfo?(caspy77)
Thanks Caspy7. Hey Dao, is this a known regression?
Flags: needinfo?(dao+bmo)
It was pointed out earlier by Philipp that the prior changeset was pretty limited.

This is assuming that the malicious change didn't somehow manifest later than when it landed.

Also, I just updated to 56 and the issue is still present.
I just discovered that if I click and drag this line down that it acts like a maximized window titlebar (the same as the new drag square on the left) where you click and pull down and now it becomes windowed/non-maximized.
Blocks: 1185482
Flags: needinfo?(dao+bmo)
Whiteboard: [photon-visual][triage]
Flags: qe-verify+
Priority: -- → P2
QA Contact: brindusa.tot
Whiteboard: [photon-visual][triage] → [photon-visual]
Hi Dão, does this live on Nightly for now? How much do we concern this issue for 55 release?
Flags: needinfo?(dao+bmo)
Caspy7, what are your Windows DPI settings?
Flags: needinfo?(dao+bmo) → needinfo?(caspy77)
Assuming you're talking about the "Change the size of text, app, and other item" setting it's 150%.
If you're talking about layout.css.dpi, it's -1.

As a side note, I saw this marked 55 unaffected, but will point out I observed this in the last build of 55, however, I'm guessing it's photon related which would exempt non-nightly builds for now.
Flags: needinfo?(caspy77)
In case it's a helpful datapoint, I tried shutting down Firefox and setting zoom to 100% and restarting but this did not help. Additionally I tried doing the same but renaming xulstore.json (also to no avail).
When i set my DPI setting to 100%, this bug is present in Firefox Release too.
This happens to me when the window is created non-maximized.

1. Make current window non-maximized
2. Open a new (non-maximided) window with Ctrl+N
3. Maximize the new window, there is this problem.

But if the window is created maximized, then it works well.
Attached patch titlebar.patchSplinter Review
OK, the problem is that #titlebar is 32px tall but only has -31px margin-bottom.

Therefore, the tabs don't fully overlap it, 1px remains above.

This is because the code used Math.min but I think Math.max is more appropriate.
Assignee: nobody → oriol-bugzilla
Attachment #8878249 - Flags: review?(dao+bmo)
Priority: P2 → P1
Comment on attachment 8878249 [details] [diff] [review]

Thanks! This seems to make sense, although I can't really test it since I can't reproduce the bug.
Attachment #8878249 - Flags: review?(dao+bmo) → review+
Pushed by
Remove 1px gap above tabs in maximzed windows. r=dao
Keywords: checkin-needed
Closed: 7 years ago
Resolution: --- → FIXED
Target Milestone: --- → Firefox 56
Iteration: --- → 56.1 - Jun 26
I'm still seeing this on today's build, but per the landing time in comment 16, should it have been included?
(In reply to Caspy7 from comment #17)
> I'm still seeing this on today's build, but per the landing time in comment
> 16, should it have been included?

Yes, and the problem is fixed for me in nightly 56.0a1 2017-06-17 build bb8eab3c3ac4147848c4c85d628ba72029978665

Now I see comment 0 says 2px but I only had 1px. So maybe you still have something which produces that extra pixel?
Caspy7, if you still have the problem, can you set, open the browser console (Ctrl+Shift+J) and post the result of this code:

{let {boxSizing, marginTop, borderTopWidth, paddingTop, height, paddingBottom, borderBottomWidth, marginBottom} = getComputedStyle(document.getElementById('titlebar')); JSON.stringify({boxSizing, marginTop, borderTopWidth, paddingTop, height, paddingBottom, borderBottomWidth, marginBottom, y: document.getElementById('tab-view-deck').getBoundingClientRect().y}, null, 2)}

Before my patch I got

  "boxSizing": "border-box",
  "marginTop": "0px",
  "borderTopWidth": "0px",
  "paddingTop": "8px",
  "height": "40px",
  "paddingBottom": "0px",
  "borderBottomWidth": "0px",
  "marginBottom": "-31px",
  "y": 9

And now it's

  "boxSizing": "border-box",
  "marginTop": "0px",
  "borderTopWidth": "0px",
  "paddingTop": "8px",
  "height": "39px",
  "paddingBottom": "0px",
  "borderBottomWidth": "0px",
  "marginBottom": "-31px",
  "y": 8
Flags: needinfo?(caspy77)
Welp, for some reason Nightly was not updating properly since Friday (the 16th). It *appeared* to update, but then things got wonky on updating till it finally linked me to the manual installer.

After an update it appears that this issue is fixed.
Flags: needinfo?(caspy77)
Flags: qe-verify+
Operating System:Windows 10 x64
Firefox version:Nightly 52.0a.1

I have tested this bug in my latest nightly browser and it cannot be reproduced.
This Bug has been resolved and fixed.

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