1204931 - When I move mouse between items in bookmark/history sidebar, I get white horizontal white lines between entries

Status: RESOLVED DUPLICATE of bug 909820

(Core :: DOM: CSS Object Model, defect)

Description

[arni2033]

Attachment: video - white horizontal white lines between entries.webm

STR:   (Win7_64, Nightly 43, 32bit, ID 20150913030204, new profile, safe mode)
1. Open bookmarks/history sidebar
2. Make sure that you have at least 5 items there
3. Move mouse from the 1st item to the last one
4. If there's no white horizontal lines, move mouse from the last item to the first one

Result:       I see white lines between items
Expectations: There should be no white lines

This persists for many, many versions. I posted it earlier there: http://forums.mozillazine.org/viewtopic.php?f=9&t=2920739 . I also saw at least 3 people which said that they're having this issue on Win7/Win Vista, and 0 people on Win7/Win Vista which said that they don't have this issue.

Also, this may be fixed by removing outline from the styling. I tested this CSS in extension "Stylish"
>   @namespace url(http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul);
>   @-moz-document url("chrome://browser/content/bookmarks/bookmarksPanel.xul"){
>     treechildren:not(.autocomplete-treebody)::-moz-tree-row { outline: none !important;   }
>   }
>   @-moz-document url("chrome://browser/content/history/history-panel.xul"){
>     treechildren:not(.autocomplete-treebody)::-moz-tree-row { outline: none !important;   }
>   }
Please note that this styling is specific for Win7 and Windows Vista: chrome://global/skin/tree.css

Comment 1

[arni2033]

Attachment: screenshot - When I move mouse between items in bookmark or history sidebar, I get white horizontal white lines between entries.png

Comment 2

[Abe - QA (:Abe_LV)]

 User Agent:	Mozilla/5.0 (Windows NT 6.1; rv:45.0) Gecko/20100101 Firefox/45.0
 Nightly 45.0a1 Build ID:  20151204030208
 and Firefox 42.0

I am unable to reproduce in the latest version.

Comment 3

[arni2033]

Attachment: testcase 1 - tree rows don't redraw outline when lose hover .xul

(In reply to Abe - QA from comment #2)
> I am unable to reproduce in the latest version.
I see you checked it on latest version... But it's still 100% reproducible on every PCs I test.
Could you confirm that you're using default Win7 theme and:
1) Try STR in comment 0 in safe mode with at least 10 items in bookmarks sidebar
   and attach screenshot of what you get after the last step.
2) Install Remote XUL Manager https://addons.mozilla.org/en-US/firefox/addon/remote-xul-manager/
   then disable hardware acceleration (restart the browser ofc), open this "testcase 1"
   and move mouse up and down within the white content area. Only 1 item should have black outline

Comment 4

[arni2033]

Attachment: screencast 2 - (testcase 1) tree rows don't redraw outline when lose hover.webm

Comment 5

[arni2033]

Abe, sorry to admit, but your QA work isn't perfect. In particular, this is a long-standing xul bug which already be reported (I just found out). That means that it's absolutely valid and reproducible.