Bug report

Required Info:

• Operating System: Ubuntu 18.04
• Installation type: Source
• Version or commit hash: 2ede683
• DDS implementation: Fast-RTPS
• Client library (if applicable): rclcpp

Steps to reproduce issue

Launch the nav stack in simulation: ros2 launch nav2_bringup nav2_simulation_launch.py simulator:=gzserver

Expected behavior

As soon as Rviz is available, it is responsive to user inputs.

Actual behavior

It takes a few seconds after launch for Rviz to become responsive:

Additional information

If the robot model is disabled, then it is responsive:

Perhaps an option is to disable it by default.