Removing last dependency of a IProjectDependenciesSubTreeProvider can leave empty group node in tree

[drewnoakes]

Visual Studio Version

17.7

Summary

When extending the dependency tree via IProjectDependenciesSubTreeProvider, if the last dependency within that extender's group is removed, the group node remains with no children. In 17.6, the group would be removed.

This is a subtle behaviour regression stemming from the rewrite in #9008.

This was reported by FireGiant with the following example:

After adding “MyLibrary”.

If we delete “MyLibrary”, we used to see the “WiX Libraries” group node also deleted prior to 17.7, but instead it remains, like this: