OT does not support editing frames/levels loaded directly from a PSD file because it cannot write any changes back to the PSD file.
You would need to manually copy the frames from the PSD loaded levels and paste them into new Raster levels if you want to edit them from within OT.
Would be nice if OT gave the option to automatically convert to editable OT Raster levels when loading or a Level PSD conversion function, similar to the Convert to vector menu option.