core/window: fix QsWindow being null for WlrLayershell

Author: outfoxxed

src/window/proxywindow.cpp

@@ -542,7 +542,8 @@ void ProxyWindowAttached::updateWindow() {
 void ProxyWindowAttached::setWindow(ProxyWindowBase* window) {
 	if (window == this->mWindow) return;
 	this->mWindow = window;
-	this->mWindowInterface = window ? qobject_cast<WindowInterface*>(window->parent()) : nullptr;
+	auto* parentInterface = window ? qobject_cast<WindowInterface*>(window->parent()) : nullptr;
+	this->mWindowInterface = parentInterface ? static_cast<QObject*>(parentInterface) : window;
 	emit this->windowChanged();
 }
 

src/window/proxywindow.hpp

@@ -220,7 +220,7 @@ class ProxyWindowAttached: public QsWindowAttached {
 
 private:
 	ProxyWindowBase* mWindow = nullptr;
-	WindowInterface* mWindowInterface = nullptr;
+	QObject* mWindowInterface = nullptr;
 
 	void setWindow(ProxyWindowBase* window);
 };