Spot on.
Looks like if I just add an empty ToolBar and use this code:
Declare Sub SetToolbarStyle Lib "AppKit" Selector "setToolbarStyle:" (handle As Ptr, value As Integer)
SetToolbarStyle(Me.Handle, 4) ' 3 = Unified, 0 = Automatic works as well, 4 = unified compact.
Then all is good.
Thanks @Ian_Kennedy.