1407965 - Opened "Bookmarks" menu from the Library menu glitches if Firefox window is positioned close to the bottom of the screen

Status: NEW

(Firefox :: Menus, defect, P3)

Description

[Emil Ghitta, QA [:emilghitta]]

Attachment: Issue .gif

[Affected versions]:
Firefox 57.0b7 
Firefox 58.0a1 

[Affected platforms]:
- Windows 10 64bit
- macOS 10.11.6
- Ubuntu 16.04 x64

[Steps to reproduce]:
1. Start Firefox.
2. Drag Firefox window to the bottom of the screen.
3. Click the "Library" button.
4. Click the "Bookmarks" option.

[Expected result]:
The bookmarks panel is displayed on the bottom side of Firefox window (If it has the necessary space available).

[Actual result]:
The bookmarks panel is displayed on top of the Firefox window for a very short period of time (even if there is the necessary available space to be displayed at the bottom) and then corrects itself.

[Regression range]:
This is a regression:
Last good revision: c0b4c13955e71735654c4bf53186eca801e5e461
First bad revision: 4f5ee0246c868a6b549013a142ff92089a4afd1f

Pushlog:
https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=c0b4c13955e71735654c4bf53186eca801e5e461&tochange=4f5ee0246c868a6b549013a142ff92089a4afd1f

I believe that this behavior may have been introduced by Bug 1383009. I didn't managed to reproduce this issue on builds that didn't contained the Library menu.

[Additional notes]:
For more information regarding this issue please observe the attached screencast.

I can see this issue occur with "History", "Downloads" and "Synced Tabs" menus as well.

Comment 1

[Mike de Boer [:mikedeboer]]

Neil, I think a good solution for this would be to simply disallow panel re-positioning whilst transitioning between panels. What do you think?

Comment 2

[Neil Deakin]

I think what you would want to do here is make sure that true was passed for the aIsMove argument of SetPopupPosition when the popup was being laid out and the popup wasn't being opened. (mIsOpenChanged is not true)

Comment 3

[:Gijs (he/him)]

(In reply to Emil Ghitta, QA [:emilghitta] from comment #0)
> I believe that this behavior may have been introduced by Bug 1383009. I
> didn't managed to reproduce this issue on builds that didn't contained the
> Library menu.

This doesn't make sense - bug 1383009 didn't add the library menu, it just moved it to the navbar by default. You could add it before that bug. Either way, it also sounds like this would probably be reproducible in other cases, like if you put the web developer button in the overflow panel and used that panel instead.

Comment 4

[Neil Deakin]

Attachment: Possible patch

This patch just adjusts how the move flag to SetPopupPosition is determined when called during layout.  Causes an odd issue with test_largemenu.xul that is probably related to the screen arrangement when running tests.

Comment 5

[Firefox Bug Husbandry Bot]

https://wiki.mozilla.org/Bug_Triage/Projects/Bug_Handling/Bug_Husbandry#Move_fix-optionals