I used the difference tool. Here's a fix:
1) At Start Menu > Menus > Aero > KeyBoard:TreeView Check CompositedOpaque:Bool and delete the Fillcolor property
2) Do the same at Start Menu > Menus > Aero > Hover:TreeView
and you'll be back to normal.
The Start Menu > Menus > Basic > Hover:TreeView > TreeItem > Hot will work for the hover color again. So will everything else
EDIT: I forgot you also have to remove the textcolor properties at Start Menu > Menus > Aero > KeyBoard:TreeView > TreeItem and Start Menu > Menus > Aero > Hover:TreeView > TreeItem also.