DependentUpon Add-In

[Eddie]

I finally got annoyed enough with having to add <DependentUponentries
to my C# project files manually to do something about it, so I've
written a fairly simple add-in that will find "dependencies"
automagically, and make them into sub-items.

For example, if I have some files in my project called:
Test.cs
Test.Sub1.cs
Test.Sub2.cs

Selecting Test.cs then running my add-in will make Sub1 and Sub2
sub-items of Test.cs, as you'd expect.

This is all fine and dandy, but there are a couple of problems...

If I now do a copy and paste of Test.cs, I get a file in my project
called "Copy of Test.cs", with sub-items called "Copy of Test.Sub1.cs",
etc. So far, so good...

Problem 1: if I rename this file to Test1.cs, the sub-items retain their
original copy name, and VS won't let me edit them.

Problem 2: I can't work out how to make my add-in un-sub-item these
items, in order that I can edit the names manually and recombine them.

Any suggestions?