A frustrating thing has been that in UI Builder, we cannot copy a component WITH all of its logic, to make a duplicate. When clicking on the “make a copy” button for a particular component, all the visual aspects and data binding names are copied into the new component… but any explicit logic that may have existed in the original component is lost (logic in the event handlers for example).
Therefore, if a component if very complex (with lots of sub-components and a ton of logic), if we want to use it as a basis for another component, our only options was either to reproduce all the logic bit-by-bit… or make the original component a re-usable component and then clone that reusable component to create yet another re-usable component.
However, I have stumbled upon a work-around that seems to allow for a “copy component WITH logic” operation. I think it might be useful for others so I’m describing it here:
How to duplicate components WITH logic — the trick
Create a block, make it reusable. Let’s call the reusable component “copy_block”.
Edit the reusable “copy_block” component. Place a block inside of it and check the box “pod container” for this child block (maybe give it an id “copyBlock”).
Now, on any page that contains the reusable “copy_block”, we see a POD block into which we can drop any kind of component or element:
If we have a “complex original” component for which we would like to make a copy WITH all of its logic, we drop it into the POD, then make a copy (create another instance) of the “copy_block” reusable component on our page, and then simply drag the cloned content of it’s POD back into the page… voila! We now have a copy of the original complex component on our page, with all of its logic 
@Backendless_Support : do you see anything wrong with this approach?