contenteditable within Shadow DOM does not fire 'onSelect'

[GuruM]

It seems that a contenteditable <div> within ReactShadow does not fire an onSelect event. This event is usually fired when you click anywhere within a contenteditable.

I'm actually not certain whether this is a problem with the Shadow DOM spec or a problem with react-shadow, but I thought there might be some insight here into the problem. I've made a minimal codepen that illustrates the issue: https://codepen.io/anon/pen/JJPBaL?editors=1011

If you click within the red area (outside the Shadow DOM), you'll see a log in the console, but if you click within the blue area (inside the Shadow DOM), you don't see anything written to the console.

[Wildhoney]

As onSelect for contentEditable fields is non-native, I'd assume it's an issue buried somewhere in react-dom's SelectEventPlugin. Without stepping through that code I'm not sure. However I'd presume it's attaching the event to a node above the shadow boundary, which is blocked during its bubble phase by the boundary.

What is the purpose of having an onSelect event on the contentEditable field? As onClick seems to achieve the same thing. I must be missing something.