QWebEnginePage::Copy is disabled when the user has selected text in the PDF viewer

I create a context menu by re-implementing WebEngineView::contextMenuEvent(QContextMenuEvent *event)

When the user open a PDF in the PDF Viewer and select text, page()->contextMenuData() will contain the actual selected text.

But if I add QWebEnginePage::Copy to the context menu it will appear grayed-out.

Note that Ctrl+C does work.