BUG: Motion can't start X Display Applications ("on_event_start") in Daemon mode

I want to use my monitor to show the webcam stream when event starts. My motion.cfg has a line like this: 

on_event_start vlc 127.0.0.1:8081

When event starts, Motion can take photos, can build mpeg of event BUT can not run my command.

If i use to run Motion in non daemon mode from command line with "-n" option, it works!

I tried to adding "export DISPLAY=localhost:0.0" before the command, like this:

on_event_start export DISPLAY=localhost:0.0 | vlc 127.0.0.1:8081

and give permission my X to accepting connection requests from localhost. (using "xhost localhost" command)

And it didn't work!

I tried to edit /etc/init.d/motion script to adding display there, then i edited the line like this:

DAEMON=export DISPLAY=localhost:0.0 && /usr/bin/motion


But it didn't work too!

I am waiting your helps, thanks.

Environment

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