When starting rqt with an image view, the image view does not subscribe its previously saved topic, if it does not exist already.
Example:
You start your rqt with Gazebo in a launchfile and another node outputing a video stream in a separate launchfile. You select the topic of this node and save the perspective to launch it later with the first launchfile. You start the launchfile for Gazebo, then the outputing node -> topic is not subscribed by image view. You have to click reload and select the topic again.
When starting rqt with an image view, the image view does not subscribe its previously saved topic, if it does not exist already.
Example: You start your rqt with Gazebo in a launchfile and another node outputing a video stream in a separate launchfile. You select the topic of this node and save the perspective to launch it later with the first launchfile. You start the launchfile for Gazebo, then the outputing node -> topic is not subscribed by image view. You have to click reload and select the topic again.