Cannot find slam_toolbox RViZ plugin

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Everywhere I searched on Google, they are showing that I have to be able to add the RViZ plugin for the slam_toolbox using add panel menu in RViZ.

Here is a screenshot of my RViZ: Figure

It seems that I cannot add the slam_toolbox panel!

Note that I have searched my computer for "rviz_plugins" and cannot find any RViZ plugin files except these:

/opt/ros/foxy/lib/libnav2_rviz_plugins.so
/opt/ros/foxy/share/nav2_rviz_plugins/cmake/nav2_rviz_pluginsConfig.cmake
/opt/ros/foxy/share/nav2_rviz_plugins/cmake/nav2_rviz_pluginsExport-none.cmake
/opt/ros/foxy/share/nav2_rviz_plugins/cmake/nav2_rviz_pluginsConfig-version.cmake
/opt/ros/foxy/share/nav2_rviz_plugins/cmake/nav2_rviz_pluginsExport.cmake
/opt/ros/foxy/share/ament_index/resource_index/packages/nav2_rviz_plugins
/opt/ros/foxy/share/ament_index/resource_index/rviz_common__pluginlib__plugin/nav2_rviz_plugins
/opt/ros/foxy/share/ament_index/resource_index/parent_prefix_path/nav2_rviz_plugins
/opt/ros/foxy/share/ament_index/resource_index/package_run_dependencies/nav2_rviz_plugins

Any help is appreciated.

Thanks!