Why are some icons not appearing in the workbench and editor?

Visual Studio Code uses SVG icons and there have been instances where the .SVG file extension is associated with something other than image/svg+xml. Microsoft is looking at options to fix it, but for now here's a workaround:

Using the Command Prompt:

1. Open an Administrator Command Prompt.
2. Type REG ADD HKCR\.svg /f /v "Content Type" /t REG_SZ /d image/svg+xml.

Using the Registry Editor (regedit):

1. Start regedit
2. Open the HKEY_CLASSES_ROOT key
3. Find the .svg key
4. Set its Content Type Data value to image/svg+xml
5. Exit regedit