We have decided to use Event.composed flag (false by default), instead of Event.scoped, negating its meaning. See the context: whatwg/html#1160.

That means we should have a list of exceptional events whose composed flag should be true,
instead of the current list.

Eventually, instead of having a list in one place, each event's definition should mention its composed flag should be true in each place, but I would like to have a rough consensus here.

I have made a list of events whose composed flag should be true by default, I think. The list is basically made from UIEvent spec: https://w3c.github.io/uievents/.

• Focus Events: blur, focus, focusin, focusout
• Mouse Events: click, dblclick, mousedown, mouseenter, mousemove, mosueout, mouseover, mouseup
• Wheel Events: wheel
• Input Events: beforeinput, input
• Keyboard Events: keydown, keyup
• Composition Events: compositionstart, compositionupdate, compositionend

I am going to update Blink's implementation, however, what do you think about Composition Events? I am not 100% sure what should I do for Composiition Events. Should we exclude Composition Events from here?