HTMLViewer ignores BaseURL for HTML strings on Windows

On Windows, the HTMLViewer BaseURL property and the two-argument HTMLViewer.LoadHTML(html, baseURL) method have no effect. Relative resources inside HTML loaded from a string — images, stylesheets, links — are never resolved against the supplied base URL, so documents whose relative assets work on macOS and Linux show missing assets on Windows. The documentation promises that BaseURL is the absolute base URL used when loading HTML strings with relative links or assets, with no platform caveat.

Expected behaviour: BaseURL resolves relative links and assets in HTML strings on every platform.