My source code editors rarely reformat my code to suit their tastes, unless I explicitly ask for them to do that. Configuration file editors will often reforma

My source code editors rarely reformat my code to suit their tastes, unless I explicitly ask for them to do that. Configuration file editors will often reformat the output as they like, because "you're not editing the config file directly anyway". A real-world example I've been dealing with lately are the sln, csproj, and xml files used by Visual Studio. VS is constantly rearranging entries in these files when I modify my projects. Add a dependency to one project, and VS will resort all of the dependency guids for all of the other projects in the solution. When I check my change in, the sln file looks like I've made hundreds of changes (I've got a lot of projects in my solutions) when I've only made one change. Of course, VS shouldn't be doing that. But it's probably not even intentional; I'll bet the VS developers thought "Hey, we should use XML for our sln files because it's textual and readable", and they chose an XML serialization library that was already part of the platform. Then the completely separate group responsible for the XML serialization library probably thought "Hey, when we're serializing this particular type of data structure, let's sort the list elements by something arbitrary, like their memory address", and now your sln file gets re-arranged every time you modify it. This can happen to any xml-based configuration file that doesn't have strict ordering as part of the schema.