Using a dark theme in KDE with Gnome applications (e.g., Firefox)

Question

I prefer the breeze-dark KDE theme. Unfortunately, some gnome apps (such as Firefox) are problematic. In particular, in text input fields in Firefox, one ends up with white text on a white background or dark text on a dark background.

I have:

Settings -> colors -> options -> apply colors to non-Qt applications enabled

Settings -> Application Style -> Gnome Application Style (GTK):
    GTK3 Theme: Adwaita-dark
    Icon theme: Adwaita

I am not aware of any Adwaita-dark icon theme after extensive searching.

To enable breeze-dark for KDE I have:

Settings->Application Style-> Widget Style: Breeze
Settings->Workspace Theme -> Desktop Theme: Breeze Dark

It should not be necessary, but I have also installed https://addons.mozilla.org/en-Us/firefox/addon/breeze-dark/.

cat ~/.config/gtk-3.0/settings.ini

[Settings]
gtk-application-prefer-dark-theme=true
gtk-button-images=1
gtk-cursor-theme-name=ComixCursors-Opaque-Orange
gtk-fallback-icon-theme=Numix-Circle
gtk-font-name=Liberation Sans Regular 11
gtk-icon-theme-name=Adwaita
gtk-menu-images=1
gtk-primary-button-warps-slider=1
gtk-theme-name=Adwaita-dark
gtk-toolbar-style=GTK_TOOLBAR_ICONS

After all of this, Firefox text input fields still have either white text on a white background or dark text on a dark background, making them impossible to read. (Temporary workaround is to highlight the text in a field so I can see what was entered, but that is very clumsy.)

The following question claim this closely related issue was a bug that was fixed: KDE - Problem with dark themes

However, I a running Arch Linux with the latest KDE Plasma5 and what appears to be the same issue still exists. However, I notice it mainly in text input fields, not necessarily drop down combo boxes.

Solution 1

Tested in Plasma 5.12 (Kubuntu 18.04) and 5.14 (18.10 upgraded to backports).

I can select "Breeze Dark" for the GTK themes.

I have breeze-gtk-theme installed.

Also, look for other dark themes under "Settings -> Application Style -> Gnome Application Style (GTK)" - "Get new themes".

I have seen the Firefox problem when in the past I used dark Kvantum themes, but only in Firefox. Not happening now though.

Solution 2

My experience, GTK+ application theming doesn't work well if it's not gnome session.

You should try the lxappearance application while running KDE to apply GTK+ theme or Icon theme. Tested on KDE5 and LXQt.

I think the Pop icon theme blend well with both dark and light themes.

Solution 3

Update for KDE 5.18.3 QT 5.12.5:

did not have to install lxappearance package

GTK2/3 settings are in System Settings --> Application Style --> Gnome/GTK Application Style

My issue was with Angry IP Scanner - Breeze GTK style looked like this:

Changed to AD-BlueAgave, closed and reloaded. Now looks like this:

No additional packages necessary. Just try a few different GTK themes, and remember to close and re-open the GTK app you're having issues with to view the changes.

Comments

[Sparhawk]

Perhaps try creating a new (empty) user account and changing the settings there? Then you will know with more certainty whether the bug has been fixed.

[Jarek]

I can reproduce the issue on multiple computers and different user accounts, including a new user account.

[Sparhawk]

Ah nice. Perhaps comment on the bug if nothing else if you have the time?

[Jarek]

@Sparhawk - not sure where to file a bug report. Firefox? Nope. KDE? Nope. Gnome? Nope?

[Sparhawk]

I just followed the link trail to the question you quote, then the bug link at KDE. I figure they responded there, so it should be the right place?

[Jarek]

Interesting that lxappearance works on KDE Plasma5. Thanks for letting me know. Is this the pop icon theme you mentioned? aur.archlinux.org/packages/pop-icon-theme-git

[Arnab]

Yes, that's the Pop icon I'm referring.

[Admin]

not gnome session. Don't you mean "not gtk session"? Anyway, in Plasma I have a very good experience with GUI of most gtk applications (Firefox, Chrome, uGet, Disks).

[Admin]

In what sense lxappearance does more for selecting GTK themes than using Settings -> Application Style -> Gnome Application Style (GTK) - and then even download new ones under "Get new themes"? If Firefox looks bad with dark themes what can lxappearence fix that?