*feature*

>Warning: A component is `contentEditable` and contains `children` managed by React. It is now your responsibility to guarantee that none of those nodes are unexpectedly modified or duplicated. This is probably not intentional.

It would help heaps if I would know _which_ component is causing this.
if (this instanceof window.HTMLTimeElement) {
            return '[object HTMLUnknownElement]';
          }
          return realToString.apply(this, arguments);
        };
        Object.prototype.toString = wrappedToString; 
        ReactTestUtils.renderIntoDocument(<bar />);
        
        ReactTestUtils.renderIntoDocument(<foo />);
        ReactTestUtils.renderIntoDocument(<foo />);
        
        
        
        
        
        ReactTestUtils.renderIntoDocument(<time />);
        
        ReactTestUtils.renderIntoDocument(<hasOwnProperty />);
      } finally {
        Object.prototype.toString = realToString; 
      }
      expectDev(console.error.calls.count()).toBe(4);
      expectDev(console.error.calls.argsFor(0)[0]).toContain(
        'The tag <bar> is unrecognized in this browser',
      );
      expectDev(console.error.calls.argsFor(1)[0]).toContain(
        'The tag <foo> is unrecognized in this browser',
      );
      expectDev(console.error.calls.argsFor(2)[0]).toContain(