Icons in Flatpak Desktop Files

[hrlngrv]

I have both MATE and LXDE installed on my machine. I use MATE more often, but I use LXDE a few times a month.

I installed some Flatpak programs recently, and the .desktop files work under MATE, showing icons relatively deeply nested under /var/lib/flatpak. When I use LXDE, the .desktop entries appear in the launcher/menu, but the icons are the generic default ones, as though the icons weren't set in the .desktop files. I suspect this may be due to LXDE not searching through all directories included in the XDG_DATA_DIRS environment variable.

I've fixed this by copying the .desktop files into ~/.local/share/applications and using full pathnames for the icon files. I view this as suboptimal. I could copy the icon files under /usr/share/icons/hicolor, but I'd prefer to avoid that. Is there some setting which affects where LXDE searches for icon files for .desktop files?

[drooly]

What icons do the .desktop files in question refer to?
Please show us the relvant entries.