Current version 0f Dooble (1.47) doesn't yet support some website especially the complex one. The websites that I tried so far are trello.com, whatbrowser.org.
whatbrowser.org doesn't recognize Dooble because Dooble doesn't advertise its presence in user agent strings.
Perhaps later versions of WebKit will provide more support.
This is not a bug. Dooble doesn't advertise itself.