xfce4-settings-manager does not expand exec variables with no arguments in applications desktop files

Submitted by Maurizio Galli (m4u9) `@m4u9`

Assigned to Xfce Bug Triage

xfce4-settings-manager does not expand exec variables when they have no arguments.

How to reproduce:

add desktop file containing Exec=/usr/lib/YaST2/bin/sw_single_wrapper %F added to xfce4-settings-manager
launch desktop file from xfce4-settings-manager

Expected behavior: exec variable %F should be expanded to an empty string

Actual behavior: exec variable %F is not expanded but passed as argument and fails

General notes:

In this example %F is needed by Yast Software so that we can select multiple rpm packages in the file browser and install them all at the same time.
exec variables that are supported by the standard of Freedesktop.org should always be expanded. https://specifications.freedesktop.org/desktop-entry-spec/latest/ar01s07.html

This issue only occurs when launching from inside xfce4-settings-manager. Launching from Whisker menu with the same variable works as expected

Version: 4.14.1