Added close behaviour option for specific window (#3754)

Co-authored-by: Jonathan Kelley <jkelleyrtp@gmail.com>

examples/multiwindow_with_tray_icon.rs

@@ -0,0 +1,38 @@
+//! Multiwindow with tray icon example
+//!
+//! This example shows how to implement a simple multiwindow application and tray icon using dioxus.
+//! This works by spawning a new window when the user clicks a button. We have to build a new virtualdom which has its
+//! own context, root elements, etc.
+
+use dioxus::desktop::{
+    trayicon::{default_tray_icon, init_tray_icon},
+    Config, WindowCloseBehaviour,
+};
+use dioxus::prelude::*;
+
+fn main() {
+    dioxus::LaunchBuilder::desktop()
+        // We can choose the close behavior of this window to hide. See WindowCloseBehaviour for more options.
+        .with_cfg(Config::new().with_window_close_behaviour(WindowCloseBehaviour::WindowHides))
+        .launch(app);
+}
+
+fn app() -> Element {
+    // async should not be needed, check if issue 3542 has been resolved
+    let onclick = move |_| async {
+        let dom = VirtualDom::new(popup);
+        dioxus::desktop::window().new_window(dom, Default::default());
+    };
+
+    init_tray_icon(default_tray_icon(), None);
+
+    rsx! {
+        button { onclick, "New Window" }
+    }
+}
+
+fn popup() -> Element {
+    rsx! {
+        div { "This is a popup window!" }
+    }
+}