SUMMARY *** When trying to save a file using the KDE file picker on Firefox, the Show Preview Pane option is greyed out. It cannot be clicked on to activate it and F11 does not work. This only occurs on Firefox - other KDE file dialogs are unaffected. *** STEPS TO REPRODUCE 1. Do a clean install of Firefox - do nothing to modify Firefox except use about:config to set the XDG settings to 1 to enable the KDE file picker instead of the GTK file picker. 2. Run Firefox, browse to an image file on the Internet. 3. Do a Save Page As which opens the KDE File Picker. OBSERVED RESULT The Show Preview Pane option is greyed out and neither a click nor F11 can activate it. EXPECTED RESULT The Show Preview Pane should be available for activation by a mouse click or F11. SOFTWARE/OS VERSIONS Windows: macOS: Linux/KDE Plasma: openSUSE Tumbleweed Snapshot 20231012 (available in About System) KDE Plasma Version: 5.27.8 KDE Frameworks Version: 5.110.0 Qt Version: 5.15.11 ADDITIONAL INFORMATION Kernel Version: 6.5.6-1-default (64-bit) Graphics Platform; X11 Processor: Ryzen 5 2600X Ram: 64GB Graphics Processor: AMD Radeon RX 550 Series Note that the Show Preview Pane option functions normally in all file save and open operations in other KDE applications. See attached photo of the bug.
Created attachment 162328 [details] Picture of greyed out Show Preview Pane option in KDE File Picker
Can reproduce. However it doesn't happen in our reference portal test implementation, which means it's being disabled in Firefox's code somehow. I'd recommend that you submit a bug report to them. Thanks!
*** Bug 504127 has been marked as a duplicate of this bug. ***
(In reply to Nate Graham from comment #2) > I'd recommend that you submit a bug report to them. Posted to https://bugzilla.mozilla.org/show_bug.cgi?id=1966479#field-value-short_desc:~:text=2025%2D05%2D14%2018:06%20UTC-,The%20KDE%20File%20Picker%20Portal%20has%20its%20%22Preview%22%20pane%20disabled%20when%20invoked%20by%20Firefox.,-Categories%20(Firefox%20, since this reproduces for me, too, and is a pain.
(In reply to Roke Julian Lockhart Beedell from comment #4) Ah, damn. Missed the frigging link. Ignore me.
There is an issue with browsers on the openSUSE Tumbleweed system not using the KDE XDG portal and defaulting to the GTK portal. This issue occurred on my machine and the Beelink mini PC next to it (also running openSUSE Tumbleweed.) Working with Google Gemini 2.5 Pro Preview yesterday (which has an awesome amount of KDE knowledge in its training data), I came up with a (possibly temporary) fix for that, by creating and editing a portals.conf in /etc/xdg-desktop-portal as shown below: cd /etc/xdg-desktop-portal -rw-r--r-- 1 root root 24 May 14 15:10 portals.conf /etc/xdg-desktop-portal> cat portals.conf [preferred] default=kde Today, the issue of the lack of a preview panel is resolved on both my machines. I can only assume the two problems are related. It's possible something else changed, of course, so I'm just mentioning this in passing.
I don't think this is distro-specific; I can reproduce it myself on Fedora 42 KDE with KDE software built from source code. If that fixes the issue for you, perhaps the problem is in these browsers for trying to force the use of the GNOME portal or something?
KDirOperator conditionally enables preview support depending on the types of files being shown. For that it checks the current filters and if those mime types have preview support. However it fails to resolve name filters like "*.[pP][nN][gG]". But it can resolve "*.png" and "*.PNG"
A possibly relevant merge request was started @ https://invent.kde.org/plasma/xdg-desktop-portal-kde/-/merge_requests/399
Git commit 96339a76adea65071233f0cb85d05b43f2f8e548 by David Redondo. Committed on 11/06/2025 at 13:01. Pushed by davidre into branch 'master'. filechooser: Normalize name filters to something more common The upstream spec recommends to set filters in a form like *.[pP][nN][gG] to match upper and lower case extensions. This confuses our stack which expects filters to not include groups and matches case insensitively anyway. This patch converts name filters that are in the mentioned form to the more "normal" one. FIXED-IN:6.4 M +22 -0 src/filechooser.cpp https://invent.kde.org/plasma/xdg-desktop-portal-kde/-/commit/96339a76adea65071233f0cb85d05b43f2f8e548
Git commit 0b87b05a787cb5e7beb41dde569e47e81a56690c by David Redondo. Committed on 11/06/2025 at 13:11. Pushed by davidre into branch 'Plasma/6.4'. filechooser: Normalize name filters to something more common The upstream spec recommends to set filters in a form like *.[pP][nN][gG] to match upper and lower case extensions. This confuses our stack which expects filters to not include groups and matches case insensitively anyway. This patch converts name filters that are in the mentioned form to the more "normal" one. FIXED-IN:6.4 (cherry picked from commit 96339a76adea65071233f0cb85d05b43f2f8e548) Co-authored-by: David Redondo <kde@david-redondo.de> M +22 -0 src/filechooser.cpp https://invent.kde.org/plasma/xdg-desktop-portal-kde/-/commit/0b87b05a787cb5e7beb41dde569e47e81a56690c