Closed Bug 1486303 Opened 2 years ago Closed 1 year ago

Lastpass severely slows down open new tab perf


(WebExtensions :: Developer Outreach, defect)

62 Branch
Windows 10
Not set


(firefox61 affected, firefox62 affected, firefox63 affected)

Tracking Status
firefox61 --- affected
firefox62 --- affected
firefox63 --- affected


(Reporter: henry.fai.hang.chan, Unassigned)


(Depends on 1 open bug)


User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:63.0) Gecko/20100101 Firefox/63.0
Build ID: 20180823220048

Steps to reproduce:

[ (20 items) ].forEach(url =>, _blank));

Actual results:

Takes 10 seconds to open with Lastpass Addon enabled.
Takes 1 seconds to open with Lastpass Addon disabled.

Expected results:

Similar performance with Lastpass addon on or off.
Could you please provide some clearer steps to try to reproduce this issue?
Flags: needinfo?(henry.fai.hang.chan)
1. Open the developer console (F12) on any non-blank page.
2. Paste in:

[1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20].forEach(url =>'' + url, '_blank');

When LastPass addon is enabled, opening tabs is visibly much slower.
When LastPass addon is disabled (via about:addons), opening tabs is very quick.

Attempt the above steps in private browsing mode for more drastic effects: you can see flashing purple with a lot of delay when LastPass addon is enabled, while the flashing purple is much quicker when the addon is disabled.
Flags: needinfo?(henry.fai.hang.chan)
Sorry, the code should read:

[1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20].forEach(url =>'' + url, '_blank'));
Thanks for the details. I reproduced this issue on Firefox 61.0.2, Firefox 62.0b20 and on Firefox Nightly 63.0a1 on Windows 10 x 64.
Component: Untriaged → Add-ons
Ever confirmed: true
OS: Unspecified → Windows 10
Product: Firefox → Tech Evangelism
Hardware: Unspecified → x86
Version: 63 Branch → Firefox 62
Component: Add-ons → General
Product: Tech Evangelism → WebExtensions
Depends on: 613498
See Also: → 1487465

LastPass has suggested that version 4.25.0 introduced a fix that may have improved this scenario. Can we re-verify with that version?

Flags: needinfo?(henry.fai.hang.chan)

Confirm fixed. The performance difference is not noticeable now.

(I also slowed my processor to 5%. The difference in loading was ~12 seconds (off) vs ~13 seconds (on) with 2 trial runs, pretty much just noise.)

Tested LastPass version on Nightly 67 (build 20190216).

Flags: needinfo?(henry.fai.hang.chan)
Closed: 1 year ago
Resolution: --- → WORKSFORME
Component: General → Developer Outreach
Version: Firefox 62 → 62 Branch
You need to log in before you can comment on or make changes to this bug.