Technical analysis and task splitting are available there: https://docs.google.com/document/d/1D3Sr_dnpfH-UI1khB8CA1CvZhV-Pp9kv1OJIgeapz3w/edit

The DMN boxed expression editor is one of the main components in the DMN editor. It handles a variety of decision logic types, and it has many layers of complexity.

The current implementation of the boxed expression editor works fine. However, it's a Canvas based component. Even working nicely, it leads to limitations like: I) the HiDPI intermittent issue (DROOLS-5295); II) performance concerns associated with the number of rows (BAPL-1653); III) and the main limitation of not having cells with highlighted FEEL expressions.

To address these issues, this BAPL comprehends the re-write of the DMN boxed expression component by following the new architectural standards followed by Kogito-based projects.

The new boxed expression editor component must cover all features already covered by the current implementation:

• Support for Literal Expressions definition
• Support for Contexts definition
• Support for Decision Table definition
• Support for Relation definition
• Support for Function definition
• Support for Invocation definition
• Support for List definition
• Keyboard navigation
• Context menu support for applicable actions
• Input/Output columns generation based on the type of the input nodes/the type decision node

Additionally, it must support:

• Code highlight and code completion on all FEEL based cells
• Copy/Paste integration with other spreadsheets
• Support to merged cells

The new DMN boxed expression component must work as a standalone "stateless" React/TS component. It must communicate to the rest of the editor by a thin JsInterop-based interface to provide boxed expressions definitions for BKMs and Decision Nodes.

Acceptance criteria:

• As a user, I want to be able to define Literal Expressions by using the new boxed expression editor
• As a user, I want to be able to define Contexts by using the new boxed expression editor
• As a user, I want to be able to define Decision Table by using the new boxed expression editor
• As a user, I want to be able to define Relation by using the new boxed expression editor
• As a user, I want to be able to define Function by using the new boxed expression editor
• As a user, I want to be able to define Invocation by using the new boxed expression editor
• As a user, I want to be able to define List by using the new boxed expression editor
• As a user, I want to be able to navigate and edit cells by using the keyboard with shortcuts similar to the "old" boxed expression editor
• As a user, I want to be able to use the context menu to insert/delete columns
• As a user, I want to be able to use the context menu to insert/delete rows
• As a user, I want to be able to use the context menu to duplicate rows
• As a user, I want to be able to rely on fixed headers and columns (to keep the numbered column and the header row always visible)
• As a user, I want to be able to have Input/Output columns generation based on the type of the input nodes/the type decision node
• As a user, I want to be able to see cells with highlighted expressions
• As a user, I want to be able copy cells from Google Spreadsheets and paste on the boxed expressions grid
• As a user, I want to be able copy cells from boxed expressions grid and paste on Google Spreadsheets
• As a user, I want to be able to see cells with the same value merged (like the GDT editor does)