demo tour - jsxgraph is not rendered

[cerrsys]

05b - Math Diagrams
For all JSXGraph examples I get errors on the preview pane (Mac Version on Sequoia 15.7.5):

JSXGraph error:
JSXGraph: HTML container element 'zen-jxg-o7d2fumd' not found.

JSXGraph error:
JSXGraph: HTML container element 'zen-jxg-1t7o88p4' not found.

JSXGraph error:
JSXGraph: HTML container element 'zen-jxg-vfgusqhk' not found.

[adibhanna]

Thanks for the report — reproduced and fixed.

Cause: the preview renders a note into a detached buffer and only swaps it into the page afterward. JSXGraph's initBoard() looks up its container with document.getElementById against the live document (and sizes the board from the laid-out element), so on the detached buffer it couldn't find zen-jxg-… and failed. Mermaid and function-plot use different mechanisms, which is why only JSXGraph broke.

Fix: the preview now attaches the rendered note to the live DOM before running the diagram renderers, so JSXGraph boards mount correctly. Verified against the demo tour's 05b — Math Diagrams note (the three JSXGraph figures render and are draggable). The PDF export uses the same preview, so it's covered too.

Fixed in #88 — it'll ship in the next release (v2.2.0). 🙏