Content in .txt files can be searched but no hyperlink is created for the matches

According Assistant documentation search indexing is done for *.html, *.htm, and *.txt files.
http://doc.qt.io/qt-5/assistant-custom-help-viewer.html#displaying-custom-documentation

When searching some text that is found from *.txt files the matching *.txt files are listed but can't be clicked to open them to see the actual matching lines/words inside the txt file.