Huge CPU usage and RAM comsumption when idle

[Pra3t0r5]

Preliminary Checks

• I have read and understood the important section above.
• I have searched existing issues and avoided creating duplicates.
• I am not filing an enhancement request.
• I have checked that this issue cannot be reproduced on Mozilla Firefox.
• I have checked that this issue can be reproduced once I removed all my Mods and Custom CSS.

What happened?

The Zen process is through the roof almost continuously, even slowing down other applications of my fedora workstation.

Even stranger, the main process causing it according to flame graph is a chrome related extension... in firefox? wha?

Here are the profiler results:

Zen 2025-09-17 10.28 profile.json.gz

Expected behavior

When idle, i would expect lower ram usage

Actual behavior

When idle, ram and process consumption is high

Steps to reproduce

Sorry, no idea.

Screenshots and videos

No response

Version

1.15.5b (Firefox 142.0.1) (64-bit)

What platform are you seeing the problem on?

Linux (Flatpak)

What component is this issue related to?

Performance

Relevant log output if applicable

[stevenlafl]

Yep. The Isolated Web Container process fully consumes a single thread and spins CPU for me. It's been a problem for months - perhaps since I've started using it. The solution is to restart Zen. I can't figure out where it's happening because the profiler is useless in this case.

[Propheticus]

@Pra3t0r5 chrome:// has nothing to do with the browser by the same name.
"chrome" is what developers call the browser's UI.

I'll not pretend to fully get the trace, but it looks to me like it's doing an awful lot of memory management, getting triggered by some incoming "storage changed" events/calls from the extensionparent.

it's full of these (like 40 in 150ms):

Can you test with all extensions disabled? (or troubleshoot mode enabled which does this)