Flatpak theme inconsistencies with About dialogues

[digitalethics]

When using the latest Flatpak under KDE Plasma, the About Foliate window decorations and theme do not match the GTK ones that are shipped with the Flatpak. Instead it uses my Plasma theme. This is not just the case for Foliate but in fact a problem with all Flatpaks. I thought the About dialogues are part of the individual applications and not the system.

[johnfactotum]

It doesn't have anything to do with Flatpak. I think it's just KDE and other DEs/WMs setting gtk-dialogs-use-header or something, and so it uses KDE's server-side titlebar. The widgets inside the window still use the same theme as the rest of the application.