Add Accessibility by Default

[planger]

Goal

The goal of this epic is to add accessibility to standalone, VS Code, and Theia by default.

This includes:

• Keyboard navigation within the diagram
  • Panning
  • Navigating through the diagram with cursor keys (graphical, not necessarily semantical navigation)
  • Search
• Keyboard editing
  • Moving
  • Resizing
  • Renaming
  • Deleting
• Keyboard-enabled palette
  • Switching focus between diagram and palette (maybe with tab by default)
  • Enabling the search within the palette
  • Using the cursors to navigate between controls in the palette

As optional additional features:

• Focus tracker widget indicating what is currently in focus
• Grid selection on element creation
• Toast messages

Steps

Mostly this is about

1. splitting features into those that are on by default and optional features
2. applying the platform-specific keyboard and context key integrations to enable users changing the keyboard bindings in VS Code and Theia
3. introducing platform-specific settings to enable the optional additional features or some other ways to activate them at runtime (e.g. with an in-session switch)

Issues

• Provide additional default accessibility module #1128
• Enable accessibility features for Theia integration #1130
• Enable accessibility features for VSCode integration #1129
• Node creation in accessibility tools not functioning properly #1394

Related but not in scope

• Enable accessibility features for Eclipse integration #1131