react.js component: can't get keyDown events if component inside another one

JS Bin Available here

I have a component called ComponentB for which I want to get key down events:

var ComponentB = React.createClass({

  render: function() {
    return (
       <div 
           contentEditable 
           onKeyDown={this.handleKeyDown}>{this.props.data}</div>
    );
  },
  handleKeyDown: function(e) {
     console.log("B: " + e.type +"-" + e.which);
  }
});

I can get those events if this ComponentB is directly under the main/App component.

If I try to embed this component inside another component (componentA) I don't receive those events anymore (this.props.lines is an array of 3 strings) :

var ComponentA = React.createClass({
    render: function(){
        return (
          <div
            contentEditable>
            { 
              this.props.lines.map(function(line,i) {
                return <ComponentB key={i} data={line} />  
              })
            }             
          </div>
          );
    }
});

The associated JS BIN shows this behavior : if you try to edit the lines in the component A section. no event will be emitted but they will if you edit the sinbgle instance of componentB below...

Looks to me like a bug in react.js but wanted to check here first.