Wt

In case of a WPushButton receiving content from a resolved localized string, even if the TextFormat is set to XHTML, it will always be rendered as Plain in case the string contains an XHTML entity.
A simple test case:

<message id="test">
  <p>Dos &amp; Don'ts</p>
</message>

And then adding the button with:

root()->addNew<Wt::WPushButton>(Wt::WString::tr("test"), Wt::TextFormat::XHTML);

The resulting content of the button will be <p>Dos &amp; Don'ts</p>, instead of the expected Dos & Don'ts.