1397678 - Horizontal scrollbar is not displayed at all times in the Scopes panel

Status: RESOLVED FIXED

(DevTools :: Debugger, defect)

Description

[Emil Ghitta, QA [:emilghitta]]

Attachment: horizontal scrollbar.gif

[Affected versions]:
Firefox 57.0a1 (BuildId:20170906220306)
Firefox 56.0b9 (BuildId:20170903140023)

[Affected platforms]:
Windows 10 64bit
Mac 10.11.6 
Ubuntu 16.04 64bit

[Steps to reproduce]:
1. Launch Firefox.
2. Access the https://devtools-html.github.io/debugger-examples/examples/todomvc/ webpage.
3. Open the debugger.
4. Open the todo-view.js file.
5. Add a breakpoint at line 34.
6. Add an todo item in the UI.
7. Expand the "Initialize" from the Scopes panel until the items are no longer visible.

[Expected result]:
An horizontal scrollbar is displayed at the bottom of the panel as soon as the items are no longer visible.

[Actual result]:
An horizontal scrollbar is displayed at the bottom of the panel only if scrolling at the bottom of the Scopes panel.

[Regression range]:
I don't think that this is a regression.

[Additional Information]
Please observe the attached screencast for further information about this issue.

Comment 1

[Julian Descottes [:jdescottes]]

Note that having a global horizontal scrollbar comes with its own set of issues. See discussion on https://github.com/devtools-html/debugger.html/issues/3380 for instance.

If the object inspector makes the whole side panel wider, and thus creates a global horizontal scrollbar, we must be careful of not hiding all the actionable elements located on the right of the panel: close icons for breakpoints and watch expressions, icon-buttons on the top of the side panel etc...