Bug 502660

Summary: Qt style is not preserved when a new Dolphin window is opened from an existing one with --style override
Product: [Applications] dolphin Reporter: Ninjoe <niiinjoe>
Component: generalAssignee: Dolphin Bug Assignee <dolphin-bugs-null>
Status: REPORTED ---    
Severity: normal CC: dolphin-bugs-null, kdedev
Priority: NOR    
Version First Reported In: 24.12.3   
Target Milestone: ---   
Platform: Other   
OS: Linux   
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:

Description Ninjoe 2025-04-11 05:21:25 UTC 
SUMMARY
When a Dolphin window is started using the --style= argument to override the Qt style, any new window created from it does not inherit the specified style. Instead, the new window reverts to the default Qt style. In other app like Konsole and Kate, the new window do inherit the style of the parent window.

STEPS TO REPRODUCE
1. Assume Breeze default Qt style
2. Start Dolphin with dolphin --style=kvantum, a Dolphine window with kvantum Qt style appear
3. Use Ctrl-N or context menu to open a new window

OBSERVED RESULT
A new Dolphin window appear with the default Breeze style

EXPECTED RESULT
A new Dolphin window appear with the parent window's style (kvantum)

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Fedora 42
KDE Plasma Version: 6.3.4
KDE Frameworks Version: 6.12.0
Qt Version: 6.8.2

ADDITIONAL INFORMATION
I'm now using Dolphin in a different Qt style due to a recent change to Breadcrumb. Waiting for https://invent.kde.org/frameworks/kio/-/merge_requests/1842 to be released.
Comment 1 TraceyC 2025-04-14 19:12:03 UTC 
I'm not even able to launch Dolphin with a Qt style passed on command line, with either the installed version or built from git-master. There's no error using a style that exists, it just doesn't work. Dolphin launches using the Global Theme that's set

❯ /usr/bin/dolphin --style=Fusion
qt.core.qobject.connect: QObject::connect: No such signal Solid::Backends::Fstab::FstabStorageAccess::checkRequested(QString)
qt.core.qobject.connect: QObject::connect: No such signal Solid::Backends::Fstab::FstabStorageAccess::checkDone(Solid::ErrorType, QVariant, QString)
qt.core.qobject.connect: QObject::connect: No such signal Solid::Backends::Fstab::FstabStorageAccess::checkRequested(QString)
qt.core.qobject.connect: QObject::connect: No such signal Solid::Backends::Fstab::FstabStorageAccess::checkDone(Solid::ErrorType, QVariant, QString)
qt.core.qobject.connect: QObject::connect: No such signal Solid::Backends::Fstab::FstabStorageAccess::checkRequested(QString)
qt.core.qobject.connect: QObject::connect: No such signal Solid::Backends::Fstab::FstabStorageAccess::checkDone(Solid::ErrorType, QVariant, QString)

Hopefully someone else can reproduce this