Also worth considering for some folks, http://www.openfin.co ; although it is commercial and target at applications in the financial space (trading platforms, charting apps, risk management, etc) and priced accordingly.
OpenFin doesn't quite solve the same use case but it can if your only UI is via browser components and the back end is C#. We use OpenFin in that way and it's a decent product.
I'd be interested to hear more about your experience with OpenFin.