SketchUp 6 does not recognize user defined model axis.
UV Mapping is not preserved correctly for faces where the texture is
simply applied - not positioned or projected. This happens when the faces
are within a group or component that does not align to the world axis.
The issue is also seen when you explode the group / component. This is a
SketchUp bug / limitation which can only be addressed by SketchUp itself.
Insert Vertex occasionally creates new faces when there are holes in the
Rotation Gizmo’s guide line does not always appear as an infinite line.