Windows: How to create custom appcompat shims (Application Fixes)?

Question

Windows has the capability to apply shims to mis-behaving applications. Shims are used to intercept API calls and change it. For example, shims can be used to:

Answer 1

You have to think of this from Raymond Chen's point of view. Imagine if it were possible for somebody other than Microsoft to write compatibility shims. Then whenever Microsoft makes a breaking change, in addition to all their other compatibility work they will also have to write shims for the 3rd party shims that did the wrong thing. Maintaining backward compatibility is hard enough as it is.