donwloaded the latest version this morning (1.951). loaded a saved file so i could move powers around and change slots. after i take a slot away, i was unable to put it anywhere else, couldn't even put it back where i took it from.
One thing to try is to check the button cluster by the character name / archetype boxes:
If the button above 'View Active Sets' says 'Level-Up', click it to change it to 'Dynamic'.
If the button above 'View Totals' says 'Power Only', click it to change it to 'Power / Slot'.