*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.
'Warning: Invalid DOM property `class`. Did you mean `className`?\n    in div (at **)',
      );
      expectDev(normalizeCodeLocInfo(console.error.calls.argsFor(1)[0])).toBe(
        'Warning: Invalid event handler property `onclick`. Did you mean ' +
          '`onClick`?\n    in input (at **)',
      );
    });
    it('gives source code refs for unknown prop warning (ssr)', () => {
      spyOn(console, 'error');
      ReactDOMServer.renderToString(<div class="paladin" />);
      ReactDOMServer.renderToString(<input type="text" onclick="1" />);
      expectDev(console.error.calls.count()).toBe(2);
      expectDev(normalizeCodeLocInfo(console.error.calls.argsFor(0)[0])).toBe(
        'Warning: Invalid DOM property `class`. Did you mean `className`?\n    in div (at **)',
      );
      expectDev(normalizeCodeLocInfo(console.error.calls.argsFor(1)[0])).toBe(
        'Warning: Invalid event handler property `onclick`. Did you mean ' +
          '`onClick`?\n    in input (at **)',
      );
    });
    it('gives source code refs for unknown prop warning for update render', () => {
      spyOn(console, 'error');
      var container = document.createElement('div');
      ReactTestUtils.renderIntoDocument(<div className="paladin" />, container);
      expectDev(console.error.calls.count()).toBe(0);
      ReactTestUtils.renderIntoDocument(<div class="paladin" />, container);
      expectDev(console.error.calls.count()).toBe(1);
      expectDev(normalizeCodeLocInfo(console.error.calls.argsFor(0)[0])).toBe(
        'Warning: Invalid DOM property `class`. Did you mean `className`?\n    in div (at **)',
      );