Here is some additional information with regard to the use of the loadable "U" files:

Under XyWrite 4.0 for DOS, "U" files 1 - 4 are accessible by the user of the program.  There has been some confusion regarding the use of such files, basically because documentation is insufficient. Each of the "U" files was designed, although not exclusively, for a purpose. The U1 file is designed for the incorporation of user's routines.

The U2 file was designed for Command Override, although it can also be used in a manner such as the U1 file. The Command Override feature, however, can only be configured in the U2 file. This feature is outlined on pages 1-3 of the Customization Guide.

The U3 file was designed with the forethought of the XyWrite for Windows product; specifically, the buttons and Format Bar. It can also be used for user's routines as well. U5 through U9 files were added to the Windows product as reserved for use by developers for other products being developed.

The U4 file was designed to contain the help system for Ibib for XyWrite. It can be used for user's routine's as well. If Ibid is present, it is recommended to use U4 only for Ibid.

The functions $0 - $9, and $A - $Z were not ported to XyWrite 4 to be used within "U" files, and accessed directly from key assignments as with III Plus. Around the time of the product release, many of the III Plus help file issues were not at the highest level of the development schedule. As a result, many of the help frame-types from III Plus failed to function under 4.0. Many of the issues were resolved with revision 4.016. This issue will be reported as a request, however we are not scheduling further development of the DOS-based product at this time due to current projects. We are processing priority-level bugs however. These include system crash problems.

Although functionality cannot be accessed using the $ functions as with III Plus, the keyboard can be used to directly access features from the .DLG file or from U files, using the JM (Jump) function.