Auto Light/Dark theme switching does not work consistently

[stevent-64]

IPvFoo version: 2.31
Browser: Firefox 146.0-2 Snap
OS: Ubuntu 24.04.3

My primary browser is Firefox in Ubuntu, but I've observed the same issue with Firefox in Windows 11 as well.
Both browsers have the website color schemes set to automatic, and both use the Dark Brushed Metal Classic browser theme.

Whenever I start Firefox, the IPvFoo icon is set to dark mode, i.e. brightly colored. I have to manually click on the icon to change it to the correct color, i.e. dark colored. Normally, the color of the IPvFoo icon remains correctly set with newly opened tabs, but there are instances where switching to a different opened tab will have an incorrect color (bright when it should be dark) and then all other opened tabs and new tabs switch to the incorrect color. Clicking on the IPvFoo icon resets them to the correct color again.

I've yet to figure out how to reproduce this situation when it switches arbitrarily sometimes after clicking on an opened tab. However, on starting the browser it's always the wrong bright color even though the address bar for the theme is an unchanging light off-white color.

I assume that perhaps it's the theme that I'm using that may be confusing IPvFoo, but given the large number of themes to pick from in Mozilla's Add-on store, I doubt my chosen theme is unique in causing this issue with IPvFoo.

Could the option to set the color manually in the Preferences section be re-added as an override to the automatic color selection?

[pmarks-net]

Expect several days before I have time to reproduce/fix this.

In the meantime, can you confirm if the IPvFoo popup's background color agrees with the dark/lightness of your theme's background color? The popup background uses CSS prefers-color-scheme: dark, so I'm wondering if Firefox sets that correctly when using themes.

[stevent-64]

Oh dude, I'm surprised you got back to me at all this year given the season! Thanks, no hurries! The popup works fine with Firefox's System theme. When OS (Gnome) is dark style then Firefox system theme automatically goes dark style and IPvFoo's popup is correctly set to brightly colored to contrast with the darker colored address bar. When OS goes light, Firefox follows it and IPvFoo popup is correctly dark. Websites work correctly with the System theme and with my theme based off of Firefox's color scheme setting (Automatic follows OS). Firefox's System theme with correct IPvFoo color popup. Popup set in accordance with color scheme change of OS and Firefox The problem occurs with my theme of choice, Dark Brushed Metal CLASSIC On starting Firefox no matter what color scheme style chosen: After manually clicking popup to correctly set to the darker color Despite the OS set to dark or light style, and Firefox set to Automatic,Light, or Dark color scheme, the address bar in this theme always remains the same color: off-white. Technically its a dark theme but with a light address bar element. I guess since it is a dark theme the IPvFoo popup will always start with the bright color until I click on it? And it will stay like that until I open a new tab where it sometimes will revert back to the bright color until I click on it again. But as mentioned in the bug report, it's seemingly random when it switches because it doesn't revert with every new tab opened. Hence the request to allow a setting in the preferences like the previous versions had to set it permanently across sessions. Thanks for your attention to this, and let me know if you'd like me to test any new versions, or need further information. Steve

…

On 12/16/25 5:19 PM, Paul Marks wrote: *pmarks-net* left a comment (pmarks-net/ipvfoo#76) <#76 (comment)> Expect several days before I have time to reproduce/fix this. In the meantime, can you confirm if the IPvFoo popup's background color agrees with the dark/lightness of your theme's background color? The popup background uses CSS |prefers-color-scheme: dark|, so I'm wondering if Firefox sets that correctly when using themes. — Reply to this email directly, view it on GitHub <#76 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/BQTQOHIFOAQUQ3O6M5B62KL4CCHR3AVCNFSM6AAAAACPADBBCOVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTMNRSHA2TAMZSG4>. You are receiving this because you authored the thread.Message ID: ***@***.***>

[pmarks-net]

@stevent-64 can you confirm whether v2.32 fixes the problem for you?

I'm leaving this bug open to collect feedback on whether there exist cases where a manual override is required.

[stevent-64]

Well, the new version solves my problem with the dark/light setting sticking across browser restarts and opening new tabs with the theme that I use when I set it manually. So it now consistent which fixes the problem that I had. However, I did test it with Firefox's System theme and noticed it no longer autoswitches when the OS (Ubuntu and Windows) changed from Dark to Light mode and vice versa. You can click the popup and it'll change and stick, but it's a manual switch.

Also there are a couple of themes I had installed a long time ago that I tested the new version with. The themes are "Classic Red" and "Classic Black" . They're both dark mode themes, but the addressbar has a light background, so IPvFoo should display the darker colored icon for it. But unlike the theme Dark Metal Brushed Classic which I use now, I couldn't manually switch IPvFoo to use the darker color for those two themes.

For me, the issue is resolved since I can set the color manually once and it will stay set across restarts and new tab openings. But it appears the fix has affected how IPvFoo works with other themes.

[pmarks-net]

it no longer autoswitches when the OS (Ubuntu and Windows) changed from Dark to Light mode and vice versa. You can click the popup and it'll change and stick, but it's a manual switch.

That is the expected result for now. Given that background.js and popup.js can report different values for "dark mode", I decided to deprioritize background.js.

I can confirm that "Classic Red" has a white address bar but a dark-themed popup:

So at the moment, the only solution (if I care enough to solve this edge case) is a manual override.

[stevent-64]

I'm not a programmer so I don't know how much of a time sink or how much more complex your code would have to be, but it occurs to me that following the text color of the address bar would seem to be more reliable than relying on whether theme reports itself as dark or light. Obviously, some themes aren't uniformly dark or uniformly light because they have an element like the address bar which remains unchanged in either light or dark mode. If the text is dark - which usually means a light background - then display the dark icon. If it's light (usually white) then use the lighter icon.

But as far as I'm concerned, though, the issue can be closed because I can set the icon for my preferred theme and it will consistently stay set across browser restarts and opened new tabs.