I removed the icon when I first installed Firefox by right clicking it choosing Customise Toolbar and dragging it off. It's never raised it's head since. I'm on Linux though so wonder if Windows is preventing Firefox from saving the change.

As for removing it from the Tools menu you'd need to use a custom stylesheet.

To set that up go to about:config, search for toolkit.legacyUserProfileCustomizations.stylesheets and set it to true.

Go to about:profiles and click Open Directory on the Root Directory line. That will open a folder in Windows Explorer.

In that make a folder called chrome, all lower case.

Click into that and make a text file called userChrome.css — all lower-case except for the C in the middle.

Paste this into that file:—

 #menu_openFirefoxView, #firefox-view-button {display: none !important} 

Save the file and make sure it is still called userChrome.css and rename it if not. This should block both the entry in the menu and the icon on the screen.

Restart Firefox.

With disabilitiesI fount that etremely hard to do - created the folderthen coluld not open it to do anything and have no idea how to make a text file - My wrists are in agony with what I've tried already.