ms
[Violation] Forced reflow while executing JavaScript took 75ms
[Violation] Forced reflow while executing JavaScript took 32ms
```
How can I check which plugin is causing this error?
---
### Author:  [@sam](https://meta.discourse.org/u/sam)
#### Post date: [November 28, 2018, 5:02am UTC](https://meta.discourse.org/t/typeerror-cannot-read-property-id-of-undefined/102922/6 "2018-11-28T05:02:50Z")
> [@TotalSoft](#):
>
> If I disable this plugin
I know this involves a fair amount of work but do a binary search. Comment out half the plugins, then half of half and so on till you find the culprit.
---
### Author:  [@codinghorror](https://meta.discourse.org/u/codinghorror)
#### Post date: [November 28, 2018, 6:14am UTC](https://meta.discourse.org/t/typeerror-cannot-read-property-id-of-undefined/102922/7 "2018-11-28T06:14:55Z")
It kinda has to be bbcode, doesn’t it? We run the rest of those plugins on our own internal sites..
---
### Author:  [@RGJ](https://meta.discourse.org/u/RGJ)
#### Post date: [November 28, 2018, 7:10am UTC](https://meta.discourse.org/t/typeerror-cannot-read-property-id-of-undefined/102922/8 "2018-11-28T07:10:38Z")
We have seen the exact same thing after upgrading a test enviroment to latest (`3e116bb14ed788c48bff8bf800bd4f506b8fc908`) yesterday.
I have removed _all_ plugins except for the built-in, stripped all customizations, enabled safe-mode and this error message is still persisting.
It is only happening on a single site of a multisite Discourse though (!). There are no customizations (anymore). I spent an hour stripping everything bare.
We were unable to reproduce this on another testsite, but we haven’t been able to solve this specific occurence either.
Firefox yields a slightly different error by the way, `obj is undefined` while Chrome says `TypeError: Cannot read property 'id' of undefined`
I’ll try to upgrade it to latest-latest again today.
---
### Author:  [@RGJ](https://meta.discourse.org/u/RGJ)
#### Post date: [November 28, 2018, 5:22pm UTC](https://meta.discourse.org/t/typeerror-cannot-read-property-id-of-undefined/102922/9 "2018-11-28T17:22:17Z")
Updated to latest and cleaned/precompiled all assets - still an issue.
Removed all posts and categories (it’s a test environment anyway) - still an issue.
Removed all site settings - still an issue
Restored a backup from long ago - issue is gone!
Restored backup from just before I restored the backup - issue is back
So this must be somewhere in the content but where…?
The issue only shows on pages that have a topic list, and only when I (or another user) is logged in.
When I look at the stack trace (`valueForContentItem` and `computeContentItem`) it seems like it’s related to the category chooser.
Does anyone have any idea where to look?
EDIT unchecking `tagging enabled` removes the error. But still…? The forum is not even using any tags.
EDIT #2 enabling tagging on another forum on the same multisite introduces the error there as well.
---
### Author:  [@codinghorror](https://meta.discourse.org/u/codinghorror)
#### Post date: [November 28, 2018, 7:00pm UTC](https://meta.discourse.org/t/typeerror-cannot-read-property-id-of-undefined/102922/10 "2018-11-28T19:00:29Z")
Are you on latest? I remember a fix for this going out a few days ago.
---
### Author:  [@RGJ](https://meta.discourse.org/u/RGJ)
#### Post date: [November 28, 2018, 7:23pm UTC](https://meta.discourse.org/t/typeerror-cannot-read-property-id-of-undefined/102922/11 "2018-11-28T19:23:51Z")
Yes, upgraded to latest yesterday (twice) and today (twice).
Do you have any pointers about that fix? I can’t find anything that seems related.
[This one](https://meta.discourse.org/t/forum-doesnt-work-as-expected-after-latest-upgrade-tests-passed/102884) is a different issue but I think [this one is the same issue](https://meta.discourse.org/t/whos-online-plugin-discourse-whos-online/52345/189) that was incorrectly attributed to the whos-online plugin.
---
### Author:  [@codinghorror](https://meta.discourse.org/u/codinghorror)
#### Post date: [November 28, 2018, 7:34pm UTC](https://meta.discourse.org/t/typeerror-cannot-read-property-id-of-undefined/102922/12 "2018-11-28T19:34:14Z")
More or less, cc @sam @j.jaffeux @zogstrip
---
### Author:  [@sam](https://meta.discourse.org/u/sam)
#### Post date: [November 29, 2018, 3:23am UTC](https://meta.discourse.org/t/typeerror-cannot-read-property-id-of-undefined/102922/13 "2018-11-29T03:23:38Z")
Note, this is extremely high priority for us but we need a repro or even a url of a site with the issue to debug
---
### Author:  [@RGJ](https://meta.discourse.org/u/RGJ)
#### Post date: [November 29, 2018, 7:01am UTC](https://meta.discourse.org/t/typeerror-cannot-read-property-id-of-undefined/102922/15 "2018-11-29T07:01:54Z")
I’ve sent you a PM with the details.
---
### Author:  [@ZackFea](https://meta.discourse.org/u/ZackFea)
#### Post date: [November 29, 2018, 9:38am UTC](https://meta.discourse.org/t/typeerror-cannot-read-property-id-of-undefined/102922/18 "2018-11-29T09:38:59Z")
As I mentioned in the thread that @RGJ linked, at my discourse the issue does appers. You can see it here:
> **[Rivven](https://rivven.community)**
>
> Multi-Gaming-Community
If you need more informations, logs or something, let me know.
I did not found a feature that does not work yet, but the error still persist.
---
### Author:  [@j.jaffeux](https://meta.discourse.org/u/j.jaffeux)
#### Post date: [November 29, 2018, 9:55am UTC](https://meta.discourse.org/t/typeerror-cannot-read-property-id-of-undefined/102922/19 "2018-11-29T09:55:26Z")
I think this commit will fix your issues:
[https://github.com/discourse/discourse/commit/4c7dfed32ea39cde85d575ae4b60fe2a70899c76](https://github.com/discourse/discourse/commit/4c7dfed32ea39cde85d575ae4b60fe2a70899c76)
However @ZackFea I notice you do you have tags created on your site, so I’m unsure this will fix it, I have yet to recreate an issue with existing tags.
EDIT: I’m pretty sure this will fix it.
---
### Author:  [@RGJ](https://meta.discourse.org/u/RGJ)
#### Post date: [November 29, 2018, 10:21am UTC](https://meta.discourse.org/t/typeerror-cannot-read-property-id-of-undefined/102922/20 "2018-11-29T10:21:01Z")
I can confirm that that commit solves the issue. Thank you for your quick fix!
---
### Author:  [@codinghorror](https://meta.discourse.org/u/codinghorror)
#### Post date: [November 29, 2018, 12:35pm UTC](https://meta.discourse.org/t/typeerror-cannot-read-property-id-of-undefined/102922/22 "2018-11-29T12:35:46Z")