Selection color text in search panel not legible with dark theme

[Praful]

I'm using flatpak zeal 0.9.0 in Linux Mint 22.3 Cinnamon.

The searching the docs, I can't read the selected text that appears as I type. here is what it looks like:

I've tried changing the theme to another dark text and to a light text but it seems the colour is hard-coded?

I diagnosed with chatGPT and it concluded:

In Zeal 0.9.0 on Linux/Cinnamon with a dark theme, the search-results selection uses a dark-blue background with insufficient contrast against the selected text. The colour appears to come from Qt's QPalette::Highlight rather than the documentation Custom CSS. Changing GTK themes and Qt styles does not change the selection colour.

How can I change the selected text colour?

[TheJudge26]

You can use a custom Qt stylesheet to override the selection color

echo "QTreeView::item:selected { background-color: #444; }" > ~/zeal-fix.qss
flatpak run org.zealdocs.Zeal -stylesheet=~/zeal-fix.qss

If that fixes it for you, you can make it permanent by editing your Zeal shortcut file (the .desktop file). Just add -stylesheet=~/zeal-fix.qss to the end of the Exec= line.

[Praful]

@TheJudge26 thanks for replying. Your fix changes the row selection background colour. In the above screenshot, it changes the light blue. I'd like to change the colour of the dark blue highlighted text (in this case "spell") in the tree from dark blue to something more legible.

If it helps, chatgpt wrote the following

The search match highlighting in SearchItemDelegate uses QPalette::Link. On dark themes this defaults to an illegible blue. Since the delegate explicitly uses QPalette::Link for search matches, the custom Qt stylesheet cannot override it. Could the match colour be made stylesheet-configurable, or could the application palette's Link role be set appropriately for dark themes?

The relevant code is lines 963–967 of searchitemdelegate.cpp.

[TheJudge26]

Try testing this in your terminal to see if it makes the text legible

flatpak run --env=QT_STYLE_OVERRIDE=Adwaita org.zealdocs.Zeal

If that helps, you can make it permanent for the Flatpak with this command:

flatpak override --user --env=QT_STYLE_OVERRIDE=Adwaita org.zealdocs.Zeal

As for the actual code, you are entirely correct about lines 963–967. For a permanent fix, the delegate needs to check if the row is selected and use QPalette::HighlightedText instead of Link when the row is highlighted. The patch would look something like this:

if (option.state & QStyle::State_Selected) {
    painter->setPen(palette.highlightedText().color());
} else {
    painter->setPen(palette.link().color());
}

It might be worth opening a Pull Request with that exact finding and fix if you want to see it resolved in the next release

[Praful]

flatpak run --env=QT_STYLE_OVERRIDE=Adwaita org.zealdocs.Zeal

This made no difference. flatpak complained about Adwaita not being available. If it were, I guess we're relying on the link font color being a better contrast.

For a permanent fix, the delegate needs to check if the row is selected and use QPalette::HighlightedText instead of Link when the row is highlighted.

Thanks — that makes sense for the selected-row case. My original problem, though, is the QPalette::Link colour on the unselected rows while typing a search. For example, when I type "spell", the matching letters in all the results (except the selected row, which is fine) are dark blue while the rest of the text remains normal. Would the permanent fix also need to use a dark-theme-appropriate colour for the else/palette.link() case, or make the match colour configurable?