1959912 - Firefox becomes unresponsive to clicks, cannot switch tabs, or fails to load pages after uploading a big folder with DefaultResult:1

Status: NEW

(Firefox :: Data Loss Prevention, defect)

Description

[Alexandru Trif, Desktop Test Engineering [:atrif] [PTO 1-2 May]]

Attachment: 1952508_2.gif

Found in

• 138.0b5

Affected versions

• 139.0a1 (2025-04-10)
• 138.0b5

Tested platforms

• Affected platforms: Windows 10x64, Windows 11
• Unaffected platforms: Ubuntu 24, macOS

Preconditions

• Download the DLP test assets from https://drive.google.com/file/d/1yjqVRuxdKV3WnO7D2wzMgDXBuYBxUgVw/view
• Create a distribution folder inside the Firefox folder and paste the policies-2.json to it and then rename it to policies.json
• agent not running

Steps to reproduce

1. Unpack this folder and upload it to Google Drive or https://developer.mozilla.org/en-US/docs/Web/API/HTMLInputElement/webkitdirectory.

Expected result

• Firefox functions as expected.

Actual result

• Firefox becomes unresponsive to clicks, cannot switch tabs, or fails to load pages

Regression range

• Most likely not a regression.

Additional notes

• Attached a screen recording.

Comment 1

[David Parks [:handyman]]

I'm thinking this must be failing to display the thousands of warn dialogs that the default is requesting. This should be fixed by consolidating warn dialogs (bug 1921074, which details what is needed to fix it). Leaving this open instead of duping since that bug does not indicate the browser hang.

Comment 2

[BugBot [:suhaib / :marco/ :calixte]]

The severity field is not set for this bug.
:handyman, could you have a look please?

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