Firefox: Empty space displayed in popup menu when extension is pinned to Overflow Menu

[jsynowiec]

Description

Empty space is displayed on the right side of content inside the popup menu when extension is pinned to overflow menu.

Steps to Reproduce

1. Install extension
2. Right-click on the extension icon on taskbar, select "Pin to Overflow Menu"
3. Open overflow menu by clicking on the hamburger icon
4. Click on the extension icon to display the popup menu

Expected behavior: Popup menu is sized accordingly, no empty space is displayed.

Actual behavior: Popup menu is too wide, empty space is displayed.

Versions

• Extension: 2019.12.12 to 2020.7.22
• Browser: 72.0.2 to 78.0.2
• OS: macOS 10.15.3 to 10.15.6

[jsynowiec]

Few months later and it now looks even worse with that "hole" in search bar.