There was a thread on this link http://ubuntuforums.org/showthread.php?t=1927038 with same question but it is closed.
Becouse of that i am opening new one.
i have same problem with pcman on lxde, not just for folder but for files too.
For example i have 2013-05-03.wav file that have 209MB file size and 1.7GB size on disk.
is there any solution for this?