Some differences exist between the CUA architecture and the Workplace Shell implementation in OS/2 V2.0. Some of these differences may force applications to diverge from the CUA architecture, either because of the effort required to override OS/2, or because of the negative impact to system consistency or customization if the CUA guidelines are followed.
This is of particular importance for CUA Fundamental items, which provide the foundation for many of the enhancements to CUA described in the "CUA Vision" demonstration and video. Some of the discrepancies between OS/2 and CUA are beyond the control of an individual application; under these circumstances the application has no choice but to use the OS/2 conventions.
However, in other situations it is quite easy for an application to comply with the CUA guidelines rather than following the example of OS/2. To aid in this determination, an assessment of each OS/2 item has been made, and the results are summarized in Table "Fundamental Items".
The same assessment has been made for non-fundamental (Recommended) items in Table "Recommended Items". Again, where the OS/2 implementation does not force an application to differ from the CUA architecture, the developer might simply use the OS/2 Workplace Shell as an example. In such cases the product could just as easily follow the CUA recommendations and should do so for improved consistency and ease of use.
OS/2 Version 2.0 - Volume 4: Application Development provides several examples of how to modify WPS objects and their behaviors, including subclassing folders and changing their icon description. These examples should prove useful to programmers who wish to implement CUA-conforming behaviors in their OS/2 V2.0 applications.
The relevant page in the IBM Systems Application Architecture CUA Advanced Interface Design Reference is indicated in the Reference Page column in both tables, together with an indication of which entry on that page is being applied. Each page of the IBM Systems Application Architecture CUA Advanced Interface Design Reference contains a definition, a "When to use" and a "Guidelines" section. The numbering scheme used refers to the item number within a section; W is "When to use" and G is "Guidelines", so 216/G2 is read as Page 216, second item in the Guidelines section.