When using a custom panel menu with a command with no arguments and "Run in Terminal" checked, instead of getting the command run in a terminal, I'm getting just a normal xfce4-terminal, as if I had started one manually. Specifically, I get this:

This:
<app name="Test" cmd="/tmp/test" term="true"/>

Results in an interactive but otherwise empty xfce4-terminal.

This:
<app name="Test" cmd="/tmp/test stuff" term="true"/>

Results in a teminal with "/tmp/test" being executed.  The terminal here exits when the command is finished as expected.

The actual argument needs have no relationship to the command, but _any_ command  (binary, script, etc.) with no argument in a custom menu in my environ results in a an empty interactive terminal.

I added the following menu to my panel for confirmation:

<?xml version="1.0" encoding="UTF-8"?>
<xfdesktop-menu>
        <app name="Test without arg (bad)" cmd="/bin/ls" term="true"/>
        <separator/>
        <app name="Test with arg (good)" cmd="/bin/sleep 5" term="true"/>
        <separator/>
</xfdesktop-menu>