Bug 510075

Summary:	An accent colour that is too similar to that of the current colour scheme causes some elements to visually merge, until they are indistinguishable from one-another
Product:	[Frameworks and Libraries] frameworks-kcolorscheme	Reporter:	Roke Julian Lockhart Beedell <4wy78uwh>
Component:	general	Assignee:	Nicolas Fella <nicolas.fella>
Status:	RESOLVED NOT A BUG
Severity:	normal	CC:	akselmo, kdedev
Priority:	NOR
Version First Reported In:	6.18.0
Target Milestone:	---
Platform:	Fedora RPMs
OS:	Linux
Latest Commit:		Version Fixed In:
Sentry Crash Report:
Attachments:	A Screenshot Of The Colour, Suggested In The Colouration KCM A Screenshot Of A Dolphin Transferral Plasma Notification A Screenshot Of A Discover Download Progress Indication Bar AOSP 15's Comparable B&W Accent Suggestion

Description Roke Julian Lockhart Beedell 2025-09-29 23:35:34 UTC

Created attachment 185375 [details]
A Screenshot Of The Colour, Suggested In The Colouration KCM

# SUMMARY

When the user chooses a custom accent colour that matches the base colour scheme “too well”, so-to-speak (as a layman), the consequent lack of contrast may cause at least `QProgressBar`s’ progress indicators to become invisible.

# STEPS TO REPRODUCE

1. Invoke `kcmshell6 --highlight kcm_colors`.

2. Install `plasma-discover kns://wallpaperplugin.knsrc/2139746`. [^1] [^2]

3. Apply it as the wallpaper (without any media).

4. Apply `lookandfeeltool --apply org.kde.breezedark.desktop`.

5. Apply `#686b6f` as the custom accent colour (when suggested).

Thereafter, download an update via Discover, or transfer a file via Dolphin.

# OBSERVED RESULT

`QProgressBar`s’ progress indicators to become invisible

# EXPECTED RESULT

Their outlines should be defined, and/or their opacity should differ.

# SOFTWARE/OS VERSIONS

> ~~~
> Operating System: Fedora Linux 42
> KDE Plasma Version: 6.4.5
> KDE Frameworks Version: 6.18.0
> Qt Version: 6.9.2
> Kernel Version: 6.16.8-200.fc42.x86_64 (64-bit)
> Graphics Platform: Wayland
> ~~~

# ADDITIONAL INFORMATION

This might be better filed against the Breeze QStyle or QQuickStyle.

---

Citations:

[^1]: https://github.com/luisbocanegra/plasma-smart-video-wallpaper-reborn/issues/148#issuecomment-3189502992:~:text=following%20the%20DE's%20colour%20scheme

[^2]: https://bugs.kde.org/show_bug.cgi?id=509232#c0:~:text=%3E-,plasma%2Ddiscover%20kns://wallpaperplugin.knsrc/2139746,-%3E%20~~~

Relevant software:

> ~~~
> Name         : kf6-kcolorscheme
> Version      : 6.18.0
> Release      : 1.fc42
> Architecture : x86_64
> Install Date : Mon 22 Sep 2025 23:56:50 BST
> Size         : 241911
> Signature    : RSA/SHA256, Sat 20 Sep 2025 09:56:33 BST, Key ID c8ac4916105ef944
> Source RPM   : kf6-kcolorscheme-6.18.0-1.fc42.src.rpm
> Build Date   : Fri 19 Sep 2025 14:21:40 BST
> Build Host   : buildhw-x86-03.rdu3.fedoraproject.org
> Packager     : Fedora Project
> Vendor       : Fedora Project
> URL          : https://invent.kde.org/frameworks/kcolorscheme
> Bug URL      : https://bugz.fedoraproject.org/kf6-kcolorscheme
> ~~~

Comment 1 Roke Julian Lockhart Beedell 2025-09-29 23:36:12 UTC

Created attachment 185376 [details]
A Screenshot Of A Dolphin Transferral Plasma Notification

Comment 2 Roke Julian Lockhart Beedell 2025-09-29 23:36:48 UTC

Created attachment 185377 [details]
A Screenshot Of A Discover Download Progress Indication Bar

Comment 3 Akseli Lahtinen 2025-09-30 08:30:36 UTC

Meanwhile I agree this is not ideal, some colors just are not good accent colors due to this. 
I think the solution here is for the user to not use that color.

Still, maybe we should not suggest that color in the color KCM. 

Will mark this as not-a-bug, but I will share it with others, who can reopen it if this seems like something actionable.

Comment 4 Roke Julian Lockhart Beedell 2025-09-30 10:18:55 UTC

Created attachment 185389 [details]
AOSP 15's Comparable B&W Accent Suggestion

(In reply to Akseli Lahtinen from comment #3)

I really, really like this colour: I hate having my interfaces colourful, and I was always able to choose even 50% grey on Windows (whose dark mode's colour scheme isn't blue-grey). AOSP even offers me a B&W theme in its suggestions, so KDE Plasma is the sole DE I've utilised thus far that doesn't cope with it.

I'd say that, if an interface relies upon colours to distinguish between components, that's a slight accessibility failure, especially since https://invent.kde.org/plasma/kwin/-/merge_requests/8106 exists.