Jupyter Notebook: enable vertical scrolling in code block

As suggested by @Mandy, to turn on horizontal scrolling in Jupyter code window just go to Cell>Current/All Outputs>Toggle Scrolling

You can try Cell -> Current Outputs -> Toggle Scrolling in the Jupyter UI to enable the scrolling for the output of one cell.

In order to enable vertical scrolling in an output cell of the notebook, you just need to click to the left of the cell content (in the margin, you will see the area becomes slighty shaded when you are over it).

If you double click, the content of output cell will be hidden.

If you would like to hide the content of an input cell, see also Scroll windows for code in iPython (Jupyter) Notebooks?.