[Editor] Save and restore previous window mode when toggling full-screen.

editor/editor_node.cpp

@@ -2943,8 +2943,13 @@ void EditorNode::_menu_option_confirm(int p_option, bool p_confirmed) {
 			feature_profile_manager->popup_centered_clamped(Size2(900, 800) * EDSCALE, 0.8);
 		} break;
 		case SETTINGS_TOGGLE_FULLSCREEN: {
-			DisplayServer::get_singleton()->window_set_mode(DisplayServer::get_singleton()->window_get_mode() == DisplayServer::WINDOW_MODE_FULLSCREEN ? DisplayServer::WINDOW_MODE_WINDOWED : DisplayServer::WINDOW_MODE_FULLSCREEN);
-
+			DisplayServer::WindowMode mode = DisplayServer::get_singleton()->window_get_mode();
+			if (mode == DisplayServer::WINDOW_MODE_FULLSCREEN || mode == DisplayServer::WINDOW_MODE_EXCLUSIVE_FULLSCREEN) {
+				DisplayServer::get_singleton()->window_set_mode(prev_mode);
+			} else {
+				prev_mode = mode;
+				DisplayServer::get_singleton()->window_set_mode(DisplayServer::WINDOW_MODE_FULLSCREEN);
+			}
 		} break;
 		case EDITOR_SCREENSHOT: {
 			screenshot_timer->start();

editor/editor_node.h

@@ -332,6 +332,7 @@ private:
 	bool exiting = false;
 	bool dimmed = false;
 
+	DisplayServer::WindowMode prev_mode = DisplayServer::WINDOW_MODE_MAXIMIZED;
 	int old_split_ofs = 0;
 	VSplitContainer *top_split = nullptr;
 	HBoxContainer *bottom_hb = nullptr;