Fix Project Manager crash on exit.

Fix editor settings loading / saving by Project Manager.

editor/project_manager.cpp

@@ -1863,6 +1863,8 @@ void ProjectList::_bind_methods() {
 	ADD_SIGNAL(MethodInfo(SIGNAL_PROJECT_ASK_OPEN));
 }
 
+ProjectManager *ProjectManager::singleton = nullptr;
+
 void ProjectManager::_notification(int p_what) {
 	switch (p_what) {
 		case NOTIFICATION_TRANSLATION_CHANGED:
@@ -1908,10 +1910,8 @@ void ProjectManager::_notification(int p_what) {
 	}
 }
 
-Map<String, Ref<Texture2D>> ProjectManager::icon_type_cache;
-
 Ref<Texture2D> ProjectManager::_file_dialog_get_icon(const String &p_path) {
-	return icon_type_cache["ObjectHR"];
+	return singleton->icon_type_cache["ObjectHR"];
 }
 
 void ProjectManager::_build_icon_type_cache(Ref<Theme> p_theme) {
@@ -2481,6 +2481,8 @@ void ProjectManager::_version_button_pressed() {
 }
 
 ProjectManager::ProjectManager() {
+	singleton = this;
+
 	// load settings
 	if (!EditorSettings::get_singleton()) {
 		EditorSettings::create();
@@ -2870,6 +2872,7 @@ ProjectManager::ProjectManager() {
 }
 
 ProjectManager::~ProjectManager() {
+	singleton = nullptr;
 	if (EditorSettings::get_singleton()) {
 		EditorSettings::destroy();
 	}

editor/project_manager.h

@@ -50,8 +50,10 @@ enum FilterOption {
 class ProjectManager : public Control {
 	GDCLASS(ProjectManager, Control);
 
-	static Map<String, Ref<Texture2D>> icon_type_cache;
-	static void _build_icon_type_cache(Ref<Theme> p_theme);
+	Map<String, Ref<Texture2D>> icon_type_cache;
+	void _build_icon_type_cache(Ref<Theme> p_theme);
+
+	static ProjectManager *singleton;
 
 	TabContainer *tabs;
 
@@ -139,6 +141,8 @@ protected:
 	static void _bind_methods();
 
 public:
+	static ProjectManager *get_singleton() { return singleton; }
+
 	ProjectManager();
 	~ProjectManager();
 };

main/main.cpp

@@ -1212,6 +1212,10 @@ Error Main::setup(const char *execpath, int argc, char *argv[], bool p_second_ph
 		// If we didn't find a project, we fall back to the project manager.
 		project_manager = !found_project && !cmdline_tool;
 	}
+
+	if (project_manager) {
+		Engine::get_singleton()->set_project_manager_hint(true);
+	}
 #endif
 
 	GLOBAL_DEF("debug/file_logging/enable_file_logging", false);
@@ -2540,7 +2544,6 @@ bool Main::start() {
 #ifdef TOOLS_ENABLED
 		if (project_manager) {
 			Engine::get_singleton()->set_editor_hint(true);
-			Engine::get_singleton()->set_project_manager_hint(true);
 			ProjectManager *pmanager = memnew(ProjectManager);
 			ProgressDialog *progress_dialog = memnew(ProgressDialog);
 			pmanager->add_child(progress_dialog);