Maynardleung
Most of the time you only ever need to adjust (paint) the source map. It is rare to paint the target map.
If you paint the target map:
In the case of a sliding attachment, you're limiting both where on the mesh the closest point lookup can occur at the time of creating the attachment, and also where on the mesh the attachment can slide.
In the case of a fixed attachment, you are limiting where on the mesh the closest point lookup can happen at the time of attachment creation.
Hope that's clear! 😊