I don't agree. In the notebook, you can use "%pylab inline" or "%matplotlib inline" magic to have plots inline, but you can also not use it and have plots output to a separate window without any side effects in the notebook itself. Or use any other backend of your choice.

To select a previous cell just press UP in command mode (or press Esc-UP in any mode). Ref: http://nbviewer.ipython.org/github/ipython/ipython/blob/2.x/...