Select the second camera in the Control panel. Observe that the second camera is now showing and that the button for that camera is depressed.
Switch to another panel tab.
Switch back to the Control panel. The button for the second camera is still shown as depressed, but the default camera is showing. The only way to view the second camera is to click on the first camera button (which doesn't change anything) and then click on the second camera button.
Select the second camera in the Control panel. Observe that the second camera is now showing and that the button for that camera is depressed.
Switch to another panel tab.
Switch back to the Control panel. The button for the second camera is still shown as depressed, but the default camera is showing. The only way to view the second camera is to click on the first camera button (which doesn't change anything) and then click on the second camera button.