Bug: focusMode.dimOpacity is applied without bounds clamping, allowing the overlay to be set fully transparent (0.0) and become invisible to the user

[anshul23102]

Describe the bug

In main.js, startFocusModePolling reads fmSettings.dimOpacity directly from persisted settings without clamping:

sendFocusModeOpacity(
  typeof fmSettings.dimOpacity === 'number'
    ? fmSettings.dimOpacity
    : 0.1
);

sanitizeSettings validates the type as number but applies no range constraint. A manually edited settings.json or a renderer sending a patch with dimOpacity: 0 makes the visualizer completely invisible when focus mode activates. A value above 1.0 may produce undefined CSS behavior.

To Reproduce

1. Manually edit settings.json and set focusMode.dimOpacity to 0.
2. Enable focus mode.
3. Become active (low idle time). The visualizer becomes completely invisible.

Expected behavior
dimOpacity should be clamped to a safe range (e.g., 0.05 to 0.9) in the sanitizer before it is read by focus mode polling.

[anshul23102]

Hi @SamXop123, I would like to work on this issue under GSSoC '26. Please assign it to me.

assign/

GSSoC '26 contribution

[github-actions]

Thanks for opening this issue and contributing to Paraline 🌌

The maintainers will review it soon.
If applicable, please make sure to include:

• clear reproduction/details
• screenshots or recordings
• implementation ideas (optional but appreciated)

Thanks again for helping improve the project 👍

[leno23]

Opened PR #127 clamping focusMode dimOpacity to a safe range during sanitization.

[SamXop123]

Hi @anshul23102, thank you for checking this! However, if you inspect settingsStore.js at line 507, you will find that we already apply strict range constraints (input.dimOpacity >= 0 && input.dimOpacity <= 1), falling back to defaults if out of bounds.

Furthermore, allowing 0 (complete transparency) is a design requirement to let users hide the overlay entirely during activity. Closing this as by-design!