Como se cambia de color

Perdona el retraso pero es que he estado 2 semanas de viaje y no he podido usar mi PC.
Para cambiar el color de fondo de un treeview es necesario la versión 4.70 o superior de la librería comctl32.dll.
Crea un formulario con un TreeView y botón.
Declaras:
Private Declare Function SendMessage Lib "User32" Alias "SendMessageA" (ByVal hWnd As Long, ByVal wMsg As Long, ByVal wParam As Long, lParam As Long) As Long
Private Declare Function GetWindowLong Lib "User32" Alias "GetWindowLongA" (ByVal hWnd As Long, ByVal nIndex As Long) As Long
Private Declare Function SetWindowLong Lib "User32" Alias "SetWindowLongA" (ByVal hWnd As Long, ByVal nIndex As Long, ByVal dwNewLong As Long) As Long
Private Const GWL_STYLE = -16&
Private Const TVM_SETBKCOLOR = 4381&
Private Const TVM_GETBKCOLOR = 4383&
Private Const TVS_HASLINES = 2&
En form_load() pones:
Dim nodX As Node
Set nodX = TreeView1.Nodes.Add(, , "R", "Root")
Set nodX = TreeView1.Nodes.Add("R", tvwChild, "C1", "Child 1")
Set nodX = TreeView1.Nodes.Add("R", tvwChild, "C2", "Child 2")
Set nodX = TreeView1.Nodes.Add("R", tvwChild, "C3", "Child 3")
Set nodX = TreeView1.Nodes.Add("R", tvwChild, "C4", "Child 4")
nodX.EnsureVisible
TreeView1.style = tvwTreelinesText ' Style 4.
TreeView1.BorderStyle = vbFixedSingle
en el botón pones:
Dim lngStyle As Long
Call SendMessage(TreeView1.hWnd, TVM_SETBKCOLOR, 0, ByVal RGB(255, 0, 0)) 'cambiar el fondo a rojo(como tu querías)
lngStyle = GetWindowLong(TreeView1.hWnd, GWL_STYLE)
Call SetWindowLong(TreeView1.hWnd, GWL_STYLE, lngStyle - TVS_HASLINES)
Call SetWindowLong(TreeView1.hWnd, GWL_STYLE, lngStyle)