Clicking Screen reader causes the demo page to freeze
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- Dominant language
- Rust
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Description
Describe the bug
on firefox clicking on "Screen reader" under the "Backend" side panel causes the page to freeze and the following error to appear in the console:
Uncaught TypeError: can't access property "cancel", arg0 is undefined
__wbg_cancel_cad909b29551da17 https://www.egui.rs/egui_demo_app.js:469
imports.wbg.__wbg_cancel_cad909b29551da17 = function(arg0) {
arg0.cancel();
};
Log attached below
https://github.com/user-attachments/assets/9b639137-7144-4c08-af32-49f1cd518519
To Reproduce
Steps to reproduce the behavior:
- Go to www.egui.rs
- click on "Backend"
- click on "Screen reader"
Desktop:
- OS: bazzite-gnome-nvidia
- Browser: Mozilla flatpak
- Version 142.0.1 (64-bit)
Additional context
firefox-console-export-2025-9-16_16-20-25.log
I couldn't replicate this on chromium, appears to be firefox only
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Reproduce the issue at www.egui.rs in Firefox by opening Backend and selecting Screen reader, then inspect the console error in egui_demo_app.js and the attached Firefox log. Compare the behavior with Chromium and verify whether the current main branch still freezes. Done means the Screen reader demo works in Firefox without the reported cancel error.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- javascript, rust, wasm
- Domain
- accessibility, frontend, web-dev
- Issue type
- Bug
- Difficulty
- 3/5
- Estimated time
- 1-2 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 35/100