ADR-011: Floating Chat Panel Outside the Module iframe 

Context 

The initial AI Chat implementation is a full-page backend module (Admin Tools > AI Chat). To use it, editors must leave their current workspace (Page module, List module), interact with the chat, then navigate back to verify results. For workflows where the editor issues a series of content changes via AI, this creates constant context-switching.

Alternatives considered:

• Embedded iframe inside each module: Requires patching every TYPO3 core module; not feasible.
• Sidebar panel inside the module iframe: Only visible in the AI Chat module itself; disappears when navigating away.
• Floating element inside the module iframe: Iframes are isolated; an element inside one iframe cannot span the full backend.
• Floating element in the outer backend frame (``document.body``): Persists across all module navigations because it lives outside the iframe.

Decision 

Inject an <ai-chat-panel> web component into document.body of the outer TYPO3 backend frame. The component is loaded via the import map backend.module tag (the same mechanism TYPO3 core uses for toolbar items like live search), so no PHP PageRenderer call is needed. The panel uses position: fixed with z-index coordinated with TYPO3's layering scale.

The existing full-page module is retained for history browsing and extended sessions.

Consequences 

• The panel persists across all module navigations without any module cooperation.
• The panel's AJAX calls use the same ajaxUrls available in the outer frame as any toolbar item.
• z-index coordination is required: the panel sits above the scaffold header but below TYPO3 modals.
• Drag and resize use the Pointer Events API (setPointerCapture) for reliable cross-element interaction.