Function on_pre_window_load 

pub fn on_pre_window_load(
    child: impl IntoUiNode,
    handler: Handler<WindowOpenArgs>,
) -> UiNode

P On window loaded.

This event notifies once per window, after the first layout and all WindowLoadingHandle have expired or dropped.

Route

This event property uses the preview route, that is, the handler is called before the children widget handlers and before the $pn_ident handlers.