Certain 3-dot menu items don't have icons

[khrj]

Sanity checks (must complete)

• [x] I have read and followed the installation instructions in the README
• [x] I have not modified the userChrome.css file
• [x] I have tested the latest release for my Firefox version, or commit on master/beta branch (beta is for Firefox Beta only)
  Note that I'm using Firefox Developer Edition

Describe the bug The following items don't have icons in the 3-dot menu

• Open File... (Customize menu contains a nice icon that can be used here)
• Save Page As... (A floppy icon?)
• More (A '...' icon can be used here)
• Web Developer (The spanner, or the angle brackets as seen in the customize menu can be used here)

To Reproduce Steps to reproduce the behavior:

1. Enable MaterialFox
2. Click on the 3-dot menu

Screenshots

System info

• OS: macOS 10.15.6
• Firefox version: 80.0b4

[khrj]

@muckSponge Any updates on this?