I've seen that when using the graft function, the "source" graft revision is displayed in TortoiseHg, together with the other changeset information (user,date, parent, etc..). That it's not always useful, since the source commit could be present only in a local branch, or have been stripped.
Is it possible to remove this information (the commit should just look like the case when a patch has been applied)?
The source node is added to the metadata of the grafted node and would be part of the hash. You could hg export the node (which doesn't include the graft info), hg strip the original node, and hg import again.