When replacing existing file Export field contents doesn't fully replace it.
Operating system version
Mac OS X 10.6.4
Description of the issue
Export field contents doesn't properly replace the entire field contents when choosing to replace an existing file.
Steps to reproduce the problem
Start with a non-empty text file (myFile.txt) on your computer.
Insert by reference a different file (mySmallerFile.txt) into a container field. This file is non-empty and contains fewer bytes than myFile.txt.
Export field contents and chose to replace myFile.txt in the dialog.
The resulting myFile.txt file should only contain the contents of mySmallerFile.txt.
The resulting myFile.txt is the same length as the original myFile.txt and contains the entire contents of mySmallerFile.txt plus the last part of the original contents of myFile.txt.