Support apps without root window

[kdwk]

Many apps need the ability to open multiple windows and closing any window without closing the app. For example, a user would open multiple windows of a web browser and then close any opened window they choose while expecting others to stay open. Currently, Relm4 only allows closing windows that is not the main app window, and if the user closes the that the whole app closes. Supporting otherwise would allow Relm4 to be much more versatile and suitable for a much larger range of apps.

[AaronErhardt]

Currently, Relm4 only allows closing windows that is not the main app window, and if the user closes the that the whole app closes.

This is the default behavior but you can change that if you want. For example, you can use connect_close_request() to just hide the window when the user tries to close it. Or you can launch components manually instead of using RelmApp, like in this example.

That said, the question is whether Relm4 should offer a nice abstraction for this. If you have a specific use-case, we could have a look.

[kdwk]

One use case would be web browsers. Users would want to open multiple web browser windows and be able to close any one of them without closing the app. But I'll take a look at that example, thanks

[AaronErhardt]

Ok, that's a good use-case. I would suggest we write a small example for this use-case and then look how we can simplify the code with new abstractions in Relm4.