How do I get GUI Apps to run from crontab under XFce 4.4.2?

[Todd and Margo Chester]

Todd and Margo Chester wrote:
> Erik Harrison wrote:
> 
>>> It looks like it is trying to start, but doesn't finish. I think it
>>> is not finding Todd's XFce 4.4.2?
>> I dunno anything about Virtual Box, but I would guess it can't connect
>> to X because it doesn't know the display. If Virtual Box supports
>> something like --display you could use that, or just manually set
>> $DISPLAY in your shell script.
>>
> 
> Thank you for the help!
> 
> I go to the customer's site next Wednesday or Thursday.
> I will try something like this:
> 
>       DISPLAY=:0.0
>       export DISPLAY
>       EchoAll "Restarting VirtualXP"
>       EchoAll "su todd  -c /usr/bin/VBoxManage startvm VirtualXP"
>       EchoAll "`su todd  -c "/usr/bin/VBoxManage startvm VirtualXP"`"
>       EchoAll " "

Hi All,

Got this back from the Virtual Box group:

     http://forums.virtualbox.org/viewtopic.php?p=43159#43159
     Todd, whilst I think on you will need to read on how X
     authorization works with cookies and XAUTHORITY etc.
     Basically the display uses a security model to prevent
     rogue processes hijacking the display. There are ways
     to get around this, but you need to read up on it.

I have not a clue where to start.  Anyone know where to
point me?  Any good references?

Many thanks,
-T