Support Multiple Windows (Windows)

[leaanthony]

Part of #1480

[misitebao]

I think we need to design the API first, then discuss the API, and then implement it after reaching a consensus, which can reduce and avoid later changes to the API. 🙏

[leaanthony]

The initial API is what we have now in the Window* methods plus moving the settings from "application" config to a window config. The only unanswered questions right now are:

• What does a "child window" mean vs a "sibling window" - eg are they all independent?
• Can events be picked up between all the windows? Can you target a window?

I don't think there's anything that's a blocker.

[songdemei]

This is very important.How long ?

[leaanthony]

We don't work to timescales. Sorry. Multiple windows is a pretty big API breaking change so it'll be in v3.

[songdemei]

Expect v3.

[leaanthony]

Supported in v3