1. A method of simplifying maintenance of a software system organized as a plurality of software units, said software system operable to provide a plurality of use cases to users of said software system, said method comprising: receiving a list of software units and a first bug, to indicate that said list of software units have been modified to fix said first bug; identifying a list of use cases, with each use case requiring execution of at least one of said list of software units, said list of use cases being contained in said plurality of use cases; determining, at a time instant, a set of dependent bugs of a plurality of bugs, wherein said plurality of bugs are fixed earlier than said time instant in said software system, wherein a bug of said plurality of bugs is included in said set of dependent bugs only if said bug affects at least one of said list of use cases, wherein said set of dependent bugs is a subset of said plurality of bugs such that the number of bugs in said set of dependent bugs is less than the number of bugs in said plurality of dependent bugs; and displaying said set of dependent bugs as requiring further testing in view of fixing of said first bug.