JQueryUI draggable nested lists examples, as explained in the article. Blue and green can be dragged. Red not.

1. Item 1
2. 1. 1. Item 2 - P1-C1-K1
      2. Item 3 - P1-C1-K2
   2. 1. Item 4 - P1-C2-K1
      2. Item 5 - P1-C2-K2
3. Item 6
4. 1. 1. Item 7 - P2-C1-K1
      2. Item 9 - P2-C2-K1
   2. 1. Item 9 - P2-C2-K1
      2. Item 10 - P2-C2-K2

List tree: