The staff-report iframe is expanded to full content height (no nested
scrollbar), so a modal <dialog> centered in its viewport landed in the
middle of the whole document and sat off-screen unless the parent page
was scrolled there. Cross-origin means the iframe can't read the
parent's scroll position itself.
Tab.tpl now broadcasts the iframe's visible slice (webform-mw-viewport,
rAF-throttled on scroll/resize/load and after each height change), and
AttachmentLightbox pins to that slice and fills its height. Falls back
to a fixed box when no viewport message arrives (older extension), and
standalone mode keeps native centering at a taller 85vh.
Extension bumped to 0.3.1 (template change -> re-copy + cv flush on
prod). PRODUCTION_CUTOVER.md change log updated.
Joel Brock
e4085aa0f3