A small problem is that the application icons ("icons") are gray squares. How to fix this shortcoming?

3. Solving the problem with displaying Flatpak application icons in the Start menu of the LXDE shell

The *.desktop files for launching Start menu applications in LXDE are located in the ~/.local/share/applications/ folder.
Of which files that start with org correspond to Flatpak. You need to edit the Flatpak shortcut test files.

Before doing this, you need to find the paths to the icon source files in PNG format.

3.1. Getting full paths to Flatpak icon files

clear
for f in $(ls /var/lib/flatpak/exports/share/icons/hicolor/128x128/apps/*.png); do echo $f; done

To display a list of 64x64 icons:

for f in $(ls /var/lib/flatpak/exports/share/icons/hicolor/64x64/apps/*.png); do echo $f; done

The optimal icon size for the LXDE menu is 16x16 pixels. Only Mozilla FireFox has this size, 16x16, so you have to use larger Flatpak app icons.

/var/lib/flatpak/exports/share/icons/hicolor/64x64/apps/org.chromium.Chromium.png

/var/lib/flatpak/exports/share/icons/hicolor/64x64/apps/org.mozilla.firefox.png

The text listing the files must be selected with the mouse and copied to the clipboard - Ctrl + Shift + C.

In my case, in Flatpak browsers Chrome and FireFox: - two lines for PNG icon files.
Copied lines with file paths to the clipboard. Click on the image, release your finger and hold to enlarge:

There is no difference in performance between 64x16 and 128x128 icons.

3.2 Editing text files *.*.desktop: specifying paths to icon files in the “Icon” items

I went to the folder with desktop files ~/.local/share/applications/ . There are two files in the directory starting with "org." - from Flatpak.
(If there are no org.*...desktop files, see point 2 - you need to copy the .desktop files).

Listing org*.desktop files:
cd ~/.local/share/applications/
ls -l org*.desktop

Editing the first file - shortcut to launch Mozilla Firefox:

cd ~/.local/share/applications/
nano org.mozilla.firefox.desktop

In the “Icon” line, I deleted “org.mozilla.firefox” and pasted the text via the clipboard:

Icon=/var/lib/flatpak/exports/share/icons/hicolor/128x128/apps/org.mozilla.firefox.png

and saved and exited "Ctrl+S", "Ctrl+X".

I did the same with the second file - the Chromium shortcut:

cd ~/.local/share/applications/
nano org.chromium.Chromium.desktop

The 'Icon' line is located about 1/3 of the way from the beginning of the file. In it I replaced org.chromium.Chromium with a different path (Ctrl+Shift+V)

Icon=/var/lib/flatpak/exports/share/icons/hicolor/128x128/apps/org.chromium.Chromium.png

See screenshot (press and hold 1 finger to enlarge):

Replaced the application name at the very beginning of the file with Name=Chromium на Name=Chromium FP, to distinguish it from the Chromium version that was installed from a DEB package.

Once you save the .desktop shortcut file, the changes are applied immediately.

See screenshot (taken before changing the name in the app shortcut):

4. Solving the problem with displaying application icons from the Snap store in the Start menu of the LXDE shell

After installation, we find out from Snap where the application is located:

whereis chromium

Result:

chromium: /snap/bin/chromium

The .desktop files in Snap are in a different directory, namely /var/lib/snapd/desktop/applications:

cd /var/lib/snapd/desktop/applications
ls

As before, copy the .desktop file to ~/.local/share/applications/ and edit the local .desktop file

cp chromium_chromium.desktop  ~/.local/share/applications/
nano ~/.local/share/applications/chromium_chromium.desktop

You can correct the name from Name[ru]=Веб браузер Chromium на Name[ru]=Веб браузер Chromium S, which means "From Snap".
And save the file (Ctrl+S, Ctrl+X).

Application icons and names updated successfully:

Date of last modification: 08/07/2025 - a note about OpenBox in Linux RUNTU LITE.

Related publications

Fixing Linux Mint boot problem with integrated Intel graphics card

Stop and disable TimeShift to save disk space

Troubleshooting L2TP/IPsec connection errors "Could not add IPsec connection" and "no acceptable traffic selectors found"

Hard disk partitioning for installing Linux Mint on an old PC with BIOS in GPT mode

Updating Linux Mint 21.3 Virginia to Linux Mint 22.3 Zena