On Wayland, fix Window::is_decorated with CSD

examples/window_drag_resize.rs

@@ -52,6 +52,8 @@ fn main() {
             } => {
                 if let Some(dir) = cursor_location {
                     let _res = window.drag_resize_window(dir);
+                } else if !window.is_decorated() {
+                    let _res = window.drag_window();
                 }
             }
             WindowEvent::KeyboardInput {

src/platform_impl/linux/wayland/window/state.rs

@@ -384,7 +384,7 @@ impl WindowState {
             .map(|configure| configure.decoration_mode == DecorationMode::Client)
             .unwrap_or(false);
         if let Some(frame) = csd.then_some(self.frame.as_ref()).flatten() {
-            frame.is_hidden()
+            !frame.is_hidden()
         } else {
             // Server side decorations.
             true