I started documenting this in the Step by Step guide 2.0…
This is my interpretation but I must not be far from the truth 😉
In a panel you insert components but they are encapsulated in parent objects called modulators.
A Modulator has properties (modulator properties) and contains a Component object and a Midi object.
The Component object has generic properties valid for all components and specific component properties depending on the component type (uiLbabel, uiButton…).
The Midi object has midi properties.
When you select an object from panel, you see the different properties sections in the right side column.
In your example above, ledA1 is in the first case a modulator and in the second case a component.
This means that in the second case you cannot reach the modulator properties directly and that in the first case you need to use getComponent() to go to the component level under the modulator.