Anatomy
Header, independent scroll, collapsed Icon Rail, pinned footer and workspace are separate layout owners.
Control header
Native button with aria-expanded and aria-controls; stays reachable when collapsed.
Scrollable sections
Native details/summary, independent scroll and no hidden focusable content.
Scenario section shortcut
Each compact icon matches the expanded heading for Process scope, Conditions or References. Activation expands the panel, opens the section and focuses its summary; it is not a page-navigation or simulation command.
Optional footer
A pinned profile or Settings area can be combined with Navigation, Scenario Control, or neither. This interactive demo demonstrates working profile/Settings overlays but does not make them required Scenario Control anatomy.
States
Expanded / Collapsed are exclusive layout states, not a hover-only affordance.
Expanded
Scroll sections independently while the footer stays in place.
Collapsed
Compact avatar and Settings gear remain independent 44px actions. Their dialogs/popover open without expanding hidden rail content; section icons still match their expanded headings.
Narrow viewport
Expansion overlays the existing workspace, retaining its grid width. Escape closes and returns focus to the toggle.
Usage
Use for scenario configuration, process scope and condition controls. Compact shortcuts reveal and focus a corresponding section; this is not navigation or a simulation engine.
Small forms should use Form Section or Disclosure instead. The Workbench business model, section defaults and icons stay Consumer-owned. Do not reuse hover timers or procurement-specific semantics in WBDS.
The pinned profile and Settings footer in this interactive demo is an optional cross-variant composition, not an identifying Scenario Control behavior. Here profile opens a modal, and Settings offers a small popover leading to editable preview-only dialogs. Playback remains an optional Walkthrough variant, not the default Scenario Control Side Panel contract.
Accessibility
Native button and summary keyboard behavior; modeless overlay cannot declare aria-modal.
On desktop, both rail and workspace remain available. On narrow screens, expanded rail is a non-modal overlay with close button and Escape return; no fake modal focus trap. Native profile and settings dialogs use actual showModal, and Settings uses the popover top layer with Escape/light dismissal, focus and return-to-trigger behavior. Collapse hides scroll content and exposes accessible icon actions. Check 320px, keyboard, touch, 200% zoom, Dark, independent scrolling and non-overlapping footer.