Hi Julien,
The skeleton created by MakeSelector puts the TTree in mode where the reading of the TTree content is decomposed in ints and floats (‘MakeClass’ mode). This mode is currently incompatible with cloning the TTree (mismatch in what the writing and reading code expect). The result of MakeProxy on the other hand is compatible with CloneTree and should be such that the change in your code should be minimal.
Cheers,
Philippe.