[Bug 1835467] [NEW] Loop through search occurrences in a wegpage misses one item.

Thu Jul 4 22:46:56 UTC 2019

Public bug reported:

Hi,
This is probably the most unexpected bug that I have ever seen. Fortunately, it is benign.

How to reproduce:
- Go to the webpage https://www.w3schools.com/howto/howto_js_autocomplete.asp
- Type Ctrl+f to look for a work through the webpage.
- Search for addEventListener. Firefox successfully found 4 occurrences on the webpage.
- Using the arrows next to the search box, loop through all occurrences. Firefox then loops for the following occurrences:
1 inp.addEventListener("input", function(e) {
2 b.addEventListener("click", function(e) {
3 inp.addEventListener("keydown", function(e) { (although it is hidden by the message about cookies)
4 document.addEventListener("click", function (e) {
5 Loops back to the first occurrence inp.addEventListener("input", function(e) {
6 Again the second occurrence: b.addEventListener("click", function(e) {
7 Directly to the fourth occurrence, missing the third one: document.addEventListener("click", function (e) {
8 (goes back to 5).

In other words, although the first cycle through all occurrences was
correct, the following cycles misses the third occurrence! I have
restarted Firefox and still gets this behaviour.

If instead of clicking on the “down” arrow to look for the second
occurrence, then it is “b.addEventListener("click", function(e) {” which
is missing from the loop: it seems that whenever cycling through all
occurrences of a search in a webpage, if there is only four occurrences,
then the third one is never reached except in the first cycle.

I am sending a screenshot of the situation.

This is a very unexpected behaviour, although of minor consequences.

Regards,
Martin.

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: firefox 67.0.4+build1-0ubuntu0.18.04.1
ProcVersionSignature: Ubuntu 4.15.0-54.58-generic 4.15.18
Uname: Linux 4.15.0-54-generic x86_64
AddonCompatCheckDisabled: False
AlsaVersion: Advanced Linux Sound Architecture Driver Version k4.15.0-54-generic.
ApportVersion: 2.20.9-0ubuntu7.6
Architecture: amd64
ArecordDevices:
 **** List of CAPTURE Hardware Devices ****
 card 0: PCH [HDA Intel PCH], device 0: ALC233 Analog [ALC233 Analog]
   Subdevices: 1/1
   Subdevice #0: subdevice #0
AudioDevicesInUse:
 USER        PID ACCESS COMMAND
 /dev/snd/controlC0:  martin     1585 F.... pulseaudio
BuildID: 20190620092152
Card0.Amixer.info:
 Card hw:0 'PCH'/'HDA Intel PCH at 0x90910000 irq 95'
   Mixer name	: 'Realtek ALC233'
   Components	: 'HDA:10ec0235,17aa3825,00100002 HDA:80862882,80860101,00100000'
   Controls      : 33
   Simple ctrls  : 14
Channel: Unavailable
CurrentDesktop: LXDE
Date: Thu Jul  4 23:24:35 2019
Extensions: extensions.sqlite corrupt or missing
ForcedLayersAccel: False
IfupdownConfig:
 # interfaces(5) file used by ifup(8) and ifdown(8)
 auto lo
 iface lo inet loopback
IncompatibleExtensions: Unavailable (corrupt or non-existant compatibility.ini or extensions.sqlite)
InstallationDate: Installed on 2016-12-05 (941 days ago)
InstallationMedia: Lubuntu 16.10 "Yakkety Yak" - Release amd64 (20161012.1)
IpRoute:
 default via 192.168.1.1 dev wlp4s0 proto dhcp metric 600 
 192.168.1.0/24 dev wlp4s0 proto kernel scope link src 192.168.1.3 metric 600
Locales: extensions.sqlite corrupt or missing
MostRecentCrashID: bp-7e1f310f-034d-4a7b-b742-54df41180319
Plugins: Shockwave Flash - /usr/lib/flashplugin-installer/libflashplayer.so
PrefErrors: Unexpected character ',' before close parenthesis @ /usr/lib/firefox/omni.ja:greprefs.js:1151
PrefSources: prefs.js
Profiles: Profile0 (Default) - LastVersion=67.0.4/20190620092152 (In use)
RunningIncompatibleAddons: False
SourcePackage: firefox
SubmittedCrashIDs:
 bp-7e1f310f-034d-4a7b-b742-54df41180319
 bp-daebd85b-34c2-4ab9-88ea-1fc091180208
 bp-dd2282e2-f0cb-47f7-a13a-a16c20180102
Themes: extensions.sqlite corrupt or missing
UpgradeStatus: Upgraded to bionic on 2018-08-29 (309 days ago)
dmi.bios.date: 01/12/2016
dmi.bios.vendor: LENOVO
dmi.bios.version: CCCN19WW(V2.05)
dmi.board.asset.tag: NO Asset Tag
dmi.board.name: Lenovo B50-10
dmi.board.vendor: LENOVO
dmi.board.version: SDK0J40700 WIN
dmi.chassis.asset.tag: NO Asset Tag
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Lenovo B50-10
dmi.modalias: dmi:bvnLENOVO:bvrCCCN19WW(V2.05):bd01/12/2016:svnLENOVO:pn80QR:pvrLenovoB50-10:rvnLENOVO:rnLenovoB50-10:rvrSDK0J40700WIN:cvnLENOVO:ct10:cvrLenovoB50-10:
dmi.product.family: IDEAPAD
dmi.product.name: 80QR
dmi.product.version: Lenovo B50-10
dmi.sys.vendor: LENOVO

** Affects: firefox (Ubuntu)
     Importance: Undecided
         Status: New

** Tags: amd64 apport-bug bionic

** Attachment added: "Screenshot"
   https://bugs.launchpad.net/bugs/1835467/+attachment/5275123/+files/2019-07-04-233039_1366x768_scrot.png

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Title:
  Loop through search occurrences in a wegpage misses one item.

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