Konstru uses two IDs in Grasshopper to identify elements:
Grasshopper ID: This is the GH components ID (and iteration) representing the actual component (eg. Create Beam) which created you Konstru element. This ID is always being set by Konstru and it helps us to identify your Geometry if it hasn't been referenced from Rhino. Now this ID depends on the iteration of your component. If the order of the input geometry list changes, Konstru might have issues identifying your elements. And this is why there is another ID.
Rhino ID: If you reference your geometry from Rhino directly, Konstru uses the Rhino ID to identify your elements. If a Rhino ID is set, we don't care about the GH ID anymore because its more reliable and refers to the actual geometry.
Set Rhino ID yourself: Now what if you create your geometry in GH (so you don't have a reference) and you also won't be able to keep your geometry in the same order when using lists? No worries, we've got you covered: There is a Set Rhino ID component allowing you to set the Rhino ID of your Konstru element. This way you can specify the elements Rhino ID yourself. Just keep in mind, IDs must be unique.
This image explains what we are talking about:
Red: Component ID + iteration = Grasshopper ID.
Purple: Geometry Input, if referenced geometry: equals Rhino ID.