fix use after free

applications/gui2/src/screen.cpp

@@ -59,6 +59,12 @@ Screen::Screen() :
 }
 
 Screen::~Screen() {
+	 // removes view; onClose() callback can depend on module
+	if (active_view_) {
+		this->removeChild(active_view_);
+		active_view_ = nullptr;
+	}
+
 	for (auto [name, ptr] : modules_) {
 		std::ignore = name;
 		delete ptr;