Cannot convert content written in a syntax added dynamically in an extension

Use case:

• Install the markdown syntax extension
• Navigate to Sandbox.WebHome
• Edit and try to convert it to Markdown 1.1

Result: You won't be proposed to convert the content.

The reason is because the list of available parsers/renderers is computed in the JSX which is defined with a caching of "Long". Thus if you don't force-refresh the page you don't get it recomputed.