Occasionally, bugs get fixed despite programs depending on those bugs. They do not guarantee complete bug-compatibility between releases, or even within the sam

Occasionally, bugs get fixed despite programs depending on those bugs. They do not guarantee complete bug-compatibility between releases, or even within the same release - to do so would imply they could never fix a bug without writing a new function for the bugfix and persuading all developers to use the new function and release an update, then convincing everyone to use the updated software, even when there's no known software which depended on the buggy function's behaviour. It used to be that when Microsoft found that a specific program was getting in the way of a bugfix, they'd detect the program and perform the buggy behaviour, or they'd patch the software on-the-fly. I have no idea if they still do this.