While trying to install the KDE file picker on Arch Linux, you'll most likely encounter the following situation unless you're already using KDE softwares: You'll install kdialog expecting it to be enough to open the KDE file dialog, but instead, you'll see this:

That's the default Qt file picker. To get the KDE one, the minimum list of packages (in addition to kdialog) you need to install are those:

• plasma-integration
• breeze or breeze-icons (It can work without but: you won't have icons. Alternatively, you can use another Qt theme)

With those installed, we get the expected KDE picker. It works nicely outside of a few things, namely thumbnails (the one thing we are here for!) and previews

For those to work, you need to install the kio-extras package and a few other packages in order get full support for various formats. On most systems you probably already have a few of the packages needed for the common formats (notably libpng) but you can install the following packages for other formats:

• kimageformats (bunch of stuff, check the optional dependencies)
• qt5-imageformats (for TIFF, MNG, TGA and WBMP)
• ffmpegthumbs (for video thumbnails, you might need to toggle it on and off in Dolphin because it's a bit wonky on Arch)
• kdegraphics-thumbnailers (for PDF, Blender models, RAW files)

After installing those, make sure their previews are enabled in Dolphin's settings (the config file is in ~/.config/dolphinrc) and with all of that, you should have a working KDE file picker!

For full compatibility, you need to start programs with XDG_CURRENT_DESKTOP set to KDE (which might unfortunately cause side effects in certain cases) or for programs that supports it, GTK_USE_PORTAL set to 1 with xdg-desktop-portal and xdg-desktop-portal-kde installed should be enough. For Electron apps, make sure its version is higher than 14 as it needs this PR

Make sure xdg-desktop-portal-kde is running otherwise it won't work

You might need to restart the xdg-desktop-portal service after running xdg-desktop-portal-kde using systemctl restart --user xdg-desktop-portal

Congrats, with all that you literally installed more than 100 packages for a file picker. But it works and it's pretty so who's the winner really? 🥲