moving files to full device results in error, data loss

i cut an pasted to a full disk, pcmanfm reported an error about "splicing files failed"
this resulted in signifigant data loss.
see the mv command for proper operation. pcmanfm should fail gracefully.

1 more time, i'm moving files with cut and paste, but the operation failed. although the operation failed, pcmanfm deleted my files. pcmanfm should not delete files that were not actually moved.

**edit more info to reproduce.
mount a disk with less than 100mB free.
launch pcmanfm, use the cut option on a folder with 200mb of files
navigate to the mounted disk, paste.
should not lose 100mb of files

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: pcmanfm 0.9.10-0ubuntu2
ProcVersionSignature: Ubuntu 3.2.0-19.30-generic 3.2.11
Uname: Linux 3.2.0-19-generic x86_64
ApportVersion: 2.0.1-0ubuntu4
Architecture: amd64
Date: Wed May 23 22:46:53 2012
InstallationMedia: Lubuntu 12.04 "Precise Pangolin" - Alpha amd64+mac (20120316)
Pref_Config_System_lubuntu:
 [Preferred Applications]
 WebBrowser=firefox.desktop
 MailClient=
ProcEnviron:
 TERM=xterm
 PATH=(custom, user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: pcmanfm
UpgradeStatus: No upgrade log present (probably fresh install)