Earlier quoted context omitted.
> Thus, for Microsoft, "Windows" eventually acquired secondary meaning in the world of computer software (but not as applied to window installation in the building industry). Others can freely use "windows" in most any category of goods or services they want in the building trades but, given that the term "Windows" is now exclusively associated with a product from Microsoft in that class, not in the class of computer…
Though they forced wxWindows to rename to wxWidgets.
No doubt there was both a carrot and a stick, but who knows whether the stick would have held up in court. Trademark law could also well be different in the UK.