1421659 - Console scrolls up when output changes size

Status: RESOLVED FIXED

(DevTools :: Console, defect, P2)

Description

[Oriol Brufau [:Oriol]]

1. Open the web console
2. Fill it with whatever, so that a scrollbar appears
3. Press Shift+Enter in order to write a new line in the input area
4. The input area grows up so the scrollbar is not scrolled to the bottom.
5. Scroll the scrollbar to the bottom
6. Write some letter in the input area.

Result: the scrollbar goes up
Expected: the scrollbar remains at the place where I left it.

Comment 1

[Nicolas Chevobbe [:nchevobbe]]

This is probably jsterm height calculation acting weird here

Comment 2

[Oriol Brufau [:Oriol]]

devtools.webconsole.jsterm.codeMirror=true (which is the default for Nightly) fixes the issue.

Other builds still have this problem.

Comment 4

[Nicolas Chevobbe [:nchevobbe]]

It also happen:

• if you switch between inline and editor mode
• if you resize the editor panel
• if you resize the toolbox window

basically, any time the console output has a scrollbar and is resized.

Comment 5

[Nicolas Chevobbe [:nchevobbe]]

Attachment: Bug 1421659 - Keep console output pinned to bottom when resizing. r=bomsy.

When resizing the output, if the height was modified, the scrollbar position
was updated and could lose its pinned-to-bottom state.
This patch adds a resizeObserver to the console output node, where we
scroll the output to the bottom if it's needed.
In order to be able to do that, some changes were done in how we were
detecting that the output was pinned to the bottom.
We now have an intersection observer on the last message element,
which flips a flag when the element isn't intersecting the viewport
anymore.
Some test cases are added to ensure the console has the expected
behavior in different situations.

Depends on D74708

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/8c49d2500a16
Keep console output pinned to bottom when resizing. r=bomsy.

Comment 7

[Narcis Beleuzu [:NarcisB]]

https://hg.mozilla.org/mozilla-central/rev/8c49d2500a16