Hydrogen: Scrolling output in dock no longer works

[mlangiu]

Prerequisites

• [x] Have you checked the solutions in our troubleshooting guide for common problems ?
• [x] Have you checked that your issue isn't already filed ?
  Related issues: #785, #2026

Description

Since I work with code that frequently results in large outputs I configured the hydrogen output to be displayed in the dock by default.
Outputs that are longer than the screen height used to be viewable by simply scrolling down, however, this is no longer the

Steps to Reproduce

1. In hydrogen settings activate View output in the dock by default
2. Execute command with long output, e.g:
   python for i in range(100): print(i)
3. Note that the visible output reaches 40 and the remainder is off-screen
4. Scrolling down to see the remaining output does not work
5. The only way I found is to mark any line and use shift + ↓ to expand the selection downwards, as the visible output section is moved with the selection.
6. This 'downward selection method' however results in the output slider to disappear (see screenshots) and switching to previous or later outputs is not possible until the output view has been returned to the top (again selecting an arbitrary line and pressing shift + ↑)

Versions

OS version:
macOS Catalina 10.15.7

atom --version

Atom    : 1.54.0
Electron: 6.1.12
Chrome  : 76.0.3809.146
Node    : 12.4.0

apm --version

apm  2.5.2
npm  6.14.8
node 12.4.0 x64
atom 1.54.0
python 3.8.6
git 2.27.0

Hydrogen version:

2.14.6

Plugins

Have you installed and activated any of the Hydrogen plugins below ?

• [x] hydrogen-python
• [x] Hydrogen Launcher
• [ ] Data Explorer

Logs

[Please post any error logs and the output of the developer tools as described in our [Debugging Guide](https://nteract.gitbooks.io/hydrogen/docs/Troubleshooting.html).]

Expected behavior

Being able to scroll output

Screenshots

[2sls]

I can see the output if I click on the three lines button on the top left corner

but I also have a related issue which is that I would have expected the output dock to automatically scroll down when there is overflow. Currently it does not.

[ramantehlan]

@mlangiu and @2sls, thank you for raising the issue and providing the details.
This should be fixed with this PR #2049

[2sls]

@ramantehlan - I implemented the fix you created. Maybe I am missing something, but just wondering if there is any way for the output dock to automatically scroll to bottom when there is overflow? This would match the behavior for the inline output. Thanks!

[juliuscrn]

@2sls I think it used to be like that before this bug, so hopefully it is possible. Helps a lot with logs..

Edit: I tested. It seems that Enable Autoscroll option works as expected on inline output, but not on the output pane.

[ramantehlan]

I think we should be able to make it auto-scroll again if that was the behavioral earlier. Will take a look into it.

[juliuscrn]

thanks a lot, @ramantehlan ! just to mention that the second tab in output pane does scroll down, but not the first one.

[2sls]

@juliuscrn just to clarify the behavior I am observing:

1. The second tab autoscrolls down if you switch from the first tab. The first tab doesn't scroll at all.

2. BUT it does not scroll down automatically if you are already on the second tab when there is new output.

As an aside, I don't actually know the intended difference between the first and second tab.

[juliuscrn]

The first tab only returns outputs from a single function call, the second one accumulates them. Both are useful. With auto scroll option enabled I would say both should scroll all the way down.