User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:72.0) Gecko/20100101 Firefox/72.0

Steps to reproduce:

• Load https://riot.im/app/ (no need for an account)
• Open developer tools
• Open https://riot.im/app/bundles/2399aff5932e52cc7d90/node_modules/matrix-react-sdk/lib/Avatar.js in the debugger
• Close developer tools
• Open developer tools

Actual results:

Debugger view was empty for 7.2 seconds (after which time the tab for Avatar.js appears).

Expected results:

The tab for Avatar.js should have appeared sooner.

Process sources that are visible first

The following profiles were taken while following the last step from the reproduction instructions. You can observe from the screenshots that the tab was opened 1.5 seconds earlier.

Before: https://perfht.ml/2MGTn5t
After: https://perfht.ml/32KJedq

Hi Sorin, just checking in, are you still interested in working on this fix? Jason had pushed to try back in November and it looked like a couple tests were failing then: https://treeherder.mozilla.org/#/jobs?repo=try&revision=2e0fed8dbb7d9e93b526b8b537f84ba84344444f
Please let us know if you intend to continue working on this or not.

Hi Patrick, I'll try to pick this up again soon.

Hi Sorin, are you still planning to pick up this bug? Do you need any help?

Honza

Hi Honza, I don't think I'll pick it up. Feel free to close it.

Thanks for the update Sorin!

Logan, could we look at this bug as part of you work on Source Maps / Sources?

Honza

Sorin, can you still reproduce the problem?
Are the STR still valid?

Honza

I'll keep this on my radar as something to look into when exploring sources. The motivation behind this issue seems good, but I'd want to explore if there are alternatives that would let us avoid the explicit checks against the visible tabs.

Still valid, as are the STR.