semantic-ui dropdown menu do not work-open source projects Semantic-Org/Semantic-UI

I have been trying to build a menu using Semantic-UI. I can’t get the dropdown menus to work at all. I took a copy of the page Menu examples and pulled out everything except the tiered menu and placed it in a separate file. Only the dropdown menu will not function, though there are no errors. Can anyone tell me what I have missed?

  
    
    
        
    
      
    
    
    
    
    
    
    
    
  
  
    
      
        
          
          Friends
        
        
           Browse
        
        
           Messages
        
        
          
            
              
              
            
          
          
            More 
            
               Edit Profile
               Choose Language
               Account Settings
            
          
        
      
      
        Search
        Add
        Remove