Jupyterlab active scroll bars for long results

You have a few options:

1. Right click on cell's output -> "Enable Scrolling for Outputs". This will limit output view's height and enable scrolling, like in the classic notebook.
2. Right click on cell's output -> "Create New Output View". This will create a separate scrollable view and dock it to the bottom of the screen. You can then collapse the view in the main window so it doesn't clutter the notebook.

there is an automatic way to do this. First, you must install the addon "Stylus" (available on both Chrome and Firefox). This addon allows you to write custom CSS on websites.

Next, go to your JupyterLab page at localhost:8888/lab and click on the Stylus icon in the top right, and click "Write style for this URL"

Under the URL, i changed localhost to localhost:8888/lab. Then, I copied in this script by user Buckle2000 from Github (https://github.com/jupyterlab/jupyterlab/issues/4028#issuecomment-446820575)

.jp-OutputArea-child {
    max-height: 15em;
}

.jp-OutputArea-child .jp-OutputArea-output {
    overflow: auto;
}

Then click the Save button, and you should be good to go. I believe you can change the number 15 to make it activate for different heights. It should look like this: