In Traditional UI applications, tables can be configured and presented in two different forms:

• Optimized tables are the recommended configuration for tables. They offer better performance, support for accessibility, and iteratively receive enhancements through Pega's release process. They are semantically grids, modeled off of the ARIA authoring practice guide grid pattern.
• Non-optimized tables are historically the only type of table that was available prior to the introduction of the "Optimize code" configuration option. These tables do allow for functionality such as inline editing and Report definition as source, but offer little support in the way of accessibility and performance. Non-optimized tables are no longer receiving feature enhancements.

Given that non-optimized tables are a legacy component, they are structured using tables (HTML <table>) for layout. Typically, a single non-optimized table will introduce a 2-3 table tags in the DOM, to support resizable columns, pagination, and various other styles depending on the contents and available operations of the table. These additional tables do not represent actual data relationships and would otherwise interfere with assistive technology in providing meaningful feedback to the user. This markup structure also extends to tables in the Reporting module, which are structured similarly to standard non-optimized tables.

To address this, Pega adds the role="presentation" attribute to the layout tables generated as part of the markup of non-optimized tables. This attribute strips the <table> tag of its inherent semantics so that assistive technology does not interpret the element as another table. This ensures that layout tables are essentially ignored, and only the actual table housing the tabular data is recognized.

As mentioned above, try to make use of optimized tables as an alternative wherever possible to avoid potential accessibility issues and to take advantage of the latest improvements continuously being made.

Special thanks to Jesse Monks for his support in creating this document.