1460252 - [Intermittent] White space wrongly appears in the right side of Side View panel if it's pinned to the Overflow Menu

Status: RESOLVED DUPLICATE of bug 1448276

(WebExtensions :: Frontend, defect)

Description

[Cristina Badescu [:cbadescu], Experiments QA]

Attachment: SV - white space -pinned overflow menu.gif

[Affected versions]:
- Firefox 59.0.3 and up
- Side View 0.4.3

[Affected Platforms]:
- All Windows
- All Linux

[Prerequisites]:
- Have a clean Firefox profile with the latest Side View v0.4.3 installed from https://github.com/mozilla/side-view.
- Have the Side View sidebar open.

[Steps to reproduce]:
1. Open the Firefox browser with the profile from prerequisites.
2. Right click the "Open Side View" toolbar button and select the "Pin to Overflow Menu" context menu option.
3. Click the "More tools..." button and select the "Open Side View" tab.
4. Observe the Side View panel.

[Expected result]:
- The Side View's elements fully populate the panel's width.

[Actual result]:
- White space is displayed in the right side of the panel.

[Notes]:
- This issue is also reproducible if the scrollbar appears in the Side View panel.
- This issue is not reproducible on Mac OSes.
- Attached is a screen recording with this issue: