When using the Expert Partitioner in an already installed system, the last
screen is a summary about all the actions to apply. But once this summary is
accepted, the Expert Partitioner is completely closed, and there is no hint
about what is happening under the hood. Were all the changes correctly applied?
Has it already finished? Or is it still working? No way to know.

Maybe there should be an extra step dialog saying something like: "applying
changes". If everything was correct, the user would be informed about it, and
if anything was wrong, the error would be informed and the user should stay in
the Partitioner to try another different thing.