in src/platform_impl/macos/window.rs [659:669]
fn saved_style(&self, shared_state: &mut SharedState) -> NSWindowStyleMask {
let base_mask = shared_state
.saved_style
.take()
.unwrap_or_else(|| unsafe { self.ns_window.styleMask() });
if shared_state.resizable {
base_mask | NSWindowStyleMask::NSResizableWindowMask
} else {
base_mask & !NSWindowStyleMask::NSResizableWindowMask
}
}