1492370 - "CSS Grid is not in use on this page" displayed even when it is

Status: NEW

(DevTools :: Inspector, defect, P3)

Description

[Brian Birtles (:birtles, Feb 26~ parental leave)]

Attachment: Test

On the current Nightly (I just updated about ~1hr ago) with the attached file on Windows I am seeing "CSS Grid is not in use on this page" even when it clearly is.

Patrick tells me that with the same file on MacOS and Windows for him though. Weird.

STR:
1. Open file.
2. Open DevTools (F12)
3. Open the Inspector and expand the elements until the <form> element shows.
4. Click the <form> element.

I've tried closing and re-opening DevTools and serving the file from a local web server and it hasn't made a difference.

Comment 1

[Brian Birtles (:birtles, Feb 26~ parental leave)]

Attachment: Screenshot

Comment 2

[Brian Birtles (:birtles, Feb 26~ parental leave)]

Also, if I click the "grid" item on the left, the highlighting works, but the "Grid" section doesn't change.

Comment 3

[Brian Birtles (:birtles, Feb 26~ parental leave)]

I can repro this with my work profile but not my home profile. I'll try later to narrow down the difference although there's nothing obvious so far.

I can repro it using that same work profile on Windows and Linux so updating the platform to All.

Comment 4

[Brian Birtles (:birtles, Feb 26~ parental leave)]

I think I worked it out. My work profile had an empty string as the value for the devtools.inspector.activeSidebar pref.

I have no idea how that got set. But even if I set that now, I can reproduce the problem. If I reset the pref then the bug is fixed.

Comment 5

[Patrick Brosset <:pbro>]

We should make the code more resilient here to avoid this from happening again.
For instance, after this line: https://searchfox.org/mozilla-central/rev/94e37e71ffbfd39e6ad73ebcda5d77cce8d341ae/devtools/client/inspector/inspector.js#905
we should set a hard-coded default value for the default tab if the value is empty.

Comment 6

[Patrick Brosset <:pbro>]

This bug has not been updated in the last 3 months. Resetting the assignee field.
Please, feel free to pick it up again and add a comment outlining your plans for it if you do still intend to work on it.
This is just trying to clean our backlog of bugs and make bugs available for people.