title: Backbone collection.'at(index)' is returning multiple items
body: <p>I have a problem related with iteration of functions in Backbone. </p>
  
  <pre><code>    //View
      var PanelView = BlockView.extend({ 
          //BACKBONE PROPERTIES AND FUNCTIONS 
              className   : 'panel', 
              initialize  : function(){ 
                              BlockView.prototype.initialize.call(this);
                           }, 
              //RENDERING FUNCTIONS FOR THINGS WITH COLLECTIONS
              render      : function(){ 
                              //check special properties 
                              this.$el.css(this.model.get('css')); 
                              this.renderType(); 
                              //render data from the blocks 
                              if(this.model.get('collection')){
                                  this.model.get('collection').each(this.renderBlock, this);
                              }else{
                                  this.renderBlock(this.model.get('block')); 
                              }
                              //return to the dialog 
                              return this; 
                           }, 
              renderBlock : function(block){
                              var view = block.get('view'); 
                              var blockView = new view({model:block}); 
                              this.$el.append(blockView.render().el); 
                            },
              renderType : function(){
                              //if there is a collection, change the css of the blocks according to the display type of the panel. 
                              if(this.model.get('collection')){ 
                                  alert('rendering type');
                                  switch(this.model.get('display').type){
                                      case 'rows':    
                                          //change css of blocks to be in rows 
                                          this.model.setRows();           
                                          break; 
                                      case 'columns':
                                          this.model.setColumns(); 
                                          break;
                                      case 'grid':
                                          this.model.setGrid();  
                                  };                                          
                              }                           
                            }         
      }); //View 
  
  //Model function
      setColumns  : function(){
                      if(this.get('collection')){                 
                          var block = this.get('collection').at(0); 
                          block.get('css').width = 500 + '%'; 
                          console.log(this.get('collection').at(0)); 
                      }
      }, 
  </code></pre>
  
  <p>This seems pretty simple and so far this or each. </p>
  
  <p>Each functions were working fine until I got to this specific problem. For some reason this is changing the css values of multiple blocks even though it should not. </p>
  
  <p>This function is NOT being called multiple times, it only happens once. Even when I check out the variable in the console it returns one block in the collection. </p>
  
  <p>Can anyone help me identify why this specific piece of code would be iterating over multiple objects? </p>
  
  <p>I would attach all of the code but its multiple pages long. This is the only piece of code that seems to be functioning strangely. Any help would be appreciated! </p>