[Bug] Dark Reader broken on Firefox Nightly (not able to transition between CSS)

Bug Report

Website Address

Bug Description

Firefox Nightly 101.0a

When page initially loads, Dark Reader fails to properly select and transition light css to dark css.

Steps To Reproduce

Dark Reader configs:

{ "enabled": true, "fetchNews": false, "theme": { "mode": 1, "brightness": 100, "contrast": 100, "grayscale": 0, "sepia": 0, "useFont": false, "fontFamily": "Segoe UI", "textStroke": 0, "engine": "dynamicTheme", "stylesheet": "", "darkSchemeBackgroundColor": "#272727", "darkSchemeTextColor": "#e8e6e3", "lightSchemeBackgroundColor": "#dcdad7", "lightSchemeTextColor": "#181a1b", "scrollbarColor": "auto", "selectionColor": "auto", "styleSystemControls": false, "lightColorScheme": "Default", "darkColorScheme": "Default", "immediateModify": false }, "presets": [], "customThemes": [], "siteList": [ "www.reddit.com", "www.samsungebiz.com" ], "siteListEnabled": [ "imgur.com", "www.epicgames.com", "www.base64decode.org", ], "applyToListedOnly": false, "changeBrowserTheme": false, "syncSettings": true, "syncSitesFixes": true, "automation": "", "automationBehaviour": "OnOff", "time": { "activation": "18:00", "deactivation": "9:00" }, "location": { "latitude": null, "longitude": null }, "previewNewDesign": true, "enableForPDF": true, "enableForProtectedPages": false, "enableContextMenus": false, "detectDarkTheme": false, "notifyOfNews": false, "readNews": [ "v4-9-16", "v4-9", "attention", "dr-5-announcement", "2m-users", "automation", "product-hunt-golden-kitty-2018", "time-settings", "safari", "500k-users", "stylish", "product-hunt", "custom-site-settings", "thanks-for-contribution", "dynamic-theme" ] }

Sites were chosen at random. All sites are like this.

Go to Bloomberg or Fluent Reader and let Dark Reader load (without altering Dark Reader configs)

Observe site

Expected Behavior

Actual Behavior

If I manually turn off Dark Reader and turn it on again, it loads properly. (Expected Behavior)

Screenshots

Attached above

System Information

• OS: Windows 10
• Browser: Firefox Nightly 101
• Dark Reader Version: 4.9.48

Additional Context

[Gusted]

Dark Reader v4.9.50(which includes the fix) has been released

[emilio]

Yeah this is an issue with adopted stylesheets not working from extensions on Firefox (it’s tricky due to our security wrappers), and is being tracked in https://bugzilla.mozilla.org/show_bug.cgi?id=1766909.

As a workaround on darkreader’s side, try / catching in handleAdoptedStyleSheets would do.

That workaround would be appreciated, though the patch in that bug should also address the issue.