Sure no problem,
We use an xml file for our default layout. This means that we don't use the designer to add new tool windows to our default layout. It looks like UIStudio is now GUID based, so if I want to add a new entry directly to the xml file, it appears I must specify a GUID. For now, what I do is use the Visual Studio "Tools/Create GUID" feature. Previously, I tried to add an entry without a GUID and UIStudio crashed.
It is no big deal for me to create a GUID manually. But, to make changes to DockableWindow-converted layout easier, an auto GUID generator would make things just a little easier.