Actually that’s one feature of Playcanvas I’ve been using a lot over the years.
You can have as many windows as you like, both of the editor and the code editor, on the same or different browsers. Every change that you make is being automatically propagated to the other windows.
That’s how many people can collaborate on the same project.
On one window you can expand the assets panel, on the other the hierarchy or the inspector. If you select a camera as main view point and you move that camera, it will update the view on the other windows as well.
Ofcourse I agree it might be useful to expand this with selections but that might be confusing.
I’m not convinced that’s what most developers would want. I actually like to be able to make different selections in multiple instances of the Editor viewing the same scene. For example, sometimes, I’ll have one entity selected in one Editor and have a different entity selected in the other while I manually ‘copy’ over settings. @vaios might have his own thoughts on this.