Gnome does not honor "Hidden=true" with a custom $XDG_CONFIG_DIRS setting

Issue

• I am attempting to use the $XDG_CONFIG_DIRS environment variable to prevent Gnome from loading autostart desktop entries from /etc/xdg/autostart, but it is not working as documented:
  • The XDG Base Directory Specification specifies that the environment variable $XDG_CONFIG_DIRS can be used to define a list of directories to search for configuration files, in order of precedence.
  • The Desktop Application Autostart Specification specifies that the *.desktop files for applications to start automatically when loading the desktop environment are loaded from $XDG_CONFIG_DIRS/autostart (for each directory specified in the $XDG_CONFIG_DIRS list).
  • The Desktop Entry Specification specifies that desktop entries can be disabled by setting the value Hidden=true in the desktop entry file.
• For example, the SELinux Alert program is automatically started by the global /etc/xdg/autostart/sealertauto.desktop file.  If I want to prevent it from autostarting, I should be able to copy the file to /usr/local/etc/xdg/autostart and add a Hidden=true line to the copy, then set the environment variable XDG_CONFIG_DIRS=/usr/local/etc/xdg:/etc/xdg and the /usr/local/etc/xdg/sealertauto.desktop file will override the /etc/xdg/autostart/sealertauto.desktop file.