Fixed #470 View grid toggle in 3d not working

tools/editor/plugins/spatial_editor_plugin.cpp

@@ -2653,6 +2653,13 @@ void SpatialEditor::_menu_item_pressed(int p_option) {
 
 			grid_enabled=!is_checked;
 
+			for(int i=0;i<3;++i) {
+				if (grid_enable[i]) {
+					VisualServer::get_singleton()->instance_geometry_set_flag(grid_instance[i],VS::INSTANCE_FLAG_VISIBLE,grid_enabled);
+					grid_visible[i]=grid_enabled;
+				}
+			}
+
 			view_menu->get_popup()->set_item_checked( view_menu->get_popup()->get_item_index(p_option), grid_enabled );