http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=425811

If you create a directory called say launcher in your home directory and then run the panel from that directory all the launcher plugins die.

Normally (without the launcher dir) you get:
DBG[panel-item-manager.c:358] update_plugin_list():  + class "launcher": name=La
uncher, comment=Program launcher with optional menu, icon=gnome-fs-executable, e
xternal=0, path=/usr/lib/xfce4/panel-plugins/liblauncher.so

With the launcher dir you get:
DBG[panel-item-manager.c:358] update_plugin_list():  + class "launcher": name=La
uncher, comment=Program launcher with optional menu, icon=gnome-fs-executable, e
xternal=0, path=launcher

Note path is different.

This is because of the g_file_test in new_panel_class_from_desktop_file in panel/panel-item-manager.c:

         else if ((value = xfce_rc_read_entry (rc, "X-XFCE-Module", NULL)))
         {
            if (g_file_test (value, G_FILE_TEST_EXISTS))


So when you have a desktop file with:
X-XFCE-Module=launcher
X-XFCE-Module-Path=/usr/lib/xfce4/panel-plugins

Then it won't even consider the module path.

Possible ways to fix this:
 1. move the parsing of X-XFCE-Module-Path up before the g_file_test (i.e. swap the if and else)
 2. check for a leading / in X-XFCE-Module before the g_file_test

You might even want to do both.

I will attach the trivial patch to do the second which I've tested and works as expected.