Occasionally, VSCode fails to correctly load extensions. When you then attempt to click on a ZMF Explorer icon you may get a message for example. "Refresh Command not found" etc
 This may sometimes occur when VSCode has performed one of its regular monthly updates.

When this occurs:

Shutdown VSCode, 

Restart VSCode

Click Help - Toggle Developer Tools 

Then select Console from the top line menu bar
Attempt to open and run the extension.
Check the console for errors. Often that can provide a good indication of what actually went wrong.