Unable to detect hidden text

[BroadwayBean]

RTF has the concept of hidden text. While the library has a flag for text that has been struckthrough, it doesn't seem to have anything to indicate that certain text is visible or not:

2.4.3 :269 > doc.sections[0]
 => {:text=>"HIDDEN TEXT", :modifiers=>{:justification=>:left, :left_indent=>0.0, :right_indent=>0.0, :font=>#<RubyRTF::Font:0x00007fdbdd024ef8 @family_command=:swiss, @name="Calibri", @alternate_name="", @non_tagged_name="", @panose="020f0502020204030204", @number=31506, @character_set=0, @pitch=:variable, @theme=:himinor>, :font_size=>12.0}}