I have a data file containing Null (\000) characters.
The PP4 data pane and data selection screens will not show any characters that follow the Null characters on a record.
Example - the record contains 'ABCD\000EFG'. Only 'ABCD' is visible in the data pane.
A preview shows that the data has been read successfully and can be used on the form, but it is difficult to develop the form when the data remains invisible!
The data pane will show Null characters if they added explicitly by a user defined emulation, but not when they come from the data.
I have worked around this by editing my sample data file to replace the Nulls by Spaces.