SUMMARY First a note: HTML files are linked to open using Firefox in konqueror. If I double-click an HTML file, it opens embedded in Konqueror. If I change the opening behavior in the file associations for all file types for text to "show in external viewer", this has no effect. The HTML file is still opened in Konqueror with a double click. If I change the behavior "show in external viewer" directly in the file associations under text/html, the file is opened in Firefox with a double click, but at the same time either an error message or an information dialog appears, depending on how the checkbox "Ask if you want to save to disk instead (only for Konqueror as web browser)" is set. If the checkbox is set it gives me an Info-Dialog if you want to save the file konq:blank or open it with another application. After removing the info dialog, konqueror starts. If it's not checked, konqueror starts immediately, but gives me additionally an error dialog saying "Unable to create KIO worker. Unknown protocol konq". STEPS TO REPRODUCE 1. Set HTML-Files in the file associations to open with firefox and to open with external application. 2. Double click the HTML-File. 3. The HTML-File either opens embbeded in konqueror or an info or error dialog appears while opening in firefox. EXPECTED RESULT The HTML files should open in Firefox by double-clicking them without opening any additional dialogs. SOFTWARE/OS VERSIONS Linux: Debian bookworm (stable) KDE Plasma Version: 5.27.5 KDE Frameworks Version: 5.103.0 Qt Version: 5.15.8 Grafik-Plattform: X11 ADDITIONAL INFORMATION An Debian bullseye on the same machine with older konqueror works like expected. I can configure Konqueror so that HTML files are opened in Firefox by double-clicking them without additional dialogs.
Unfortunately, the version of Konqueror you're using isn't supported anymore since it's quite old and is still based on version 5 of Qt and the KDE Frameworks, while the current version of Konqueror is based on version 6 of Qt and KDE Frameworks. The first issue you report, however, is still happening: html files don't respect the "use setting for text group" when set to use an external application. The dialog box issue, instead, should be fixed in the coming version (24.12.0).
(In reply to Stefano Crocco from comment #1) > Unfortunately, the version of Konqueror you're using isn't supported anymore > since it's quite old and is still based on version 5 of Qt and the KDE > Frameworks, while the current version of Konqueror is based on version 6 of > Qt and KDE Frameworks. The first issue you report, however, is still > happening: html files don't respect the "use setting for text group" when > set to use an external application. The dialog box issue, instead, should be > fixed in the coming version (24.12.0). I see. Even if I wait for Debian trixie becoming stable (it seems trixie has still KDE 5), maybe konqueror has still some problems it doesn't had in an older version. Maybe this is something I have to live with when using Debian, where the software packages are not always up to date and it is difficult or impossible to use more recent packages. But thank you for your response and your efforts.