why do PMs not show up on sent folder

I often notice that when I reply to PM's there is no copy recorded in the sent folder.
Is there something I need to mark to retain a copy of the sent file?

Then every now and random then, a copy will actually surface in the sent box.

 

<img src="http://elitetrader.com/vb/attachment.php?s=&postid=2113682" BORDER=2>

 

thank you. So it seems that is selected by default. For some reason I see it now, but do not recall seeing the option this morning. I looked for it and do not recall finding the option then; it was for a private message reply.

Is there any way for a mod to verify that my most recent PM had that option? And if it was selected, why is a copy not in my sent box?

I am certain I did not de-select such an option.

 

I verified that I DID have the sent box checked. Yet, practically every time it does not store the outgoing PM in my sent box per request. Can a moderator look into why this is the case?

I also do not have the request read receipt feature as your example shows.


So clearly to start out with, something does not seem right (I am using XP SP3 and although the layout may be different under that OS, it should not mitigate my ability to store messages).