ZBrush: Merged objects still move individually

MattHatter

Iv been following along with a tutorial on zbrush and the guy hid certain sub-tools and left some visible. He then used the ones that were visible and did a 'merge visible' operation. he then appended the merged object back into the tool he was working on and used the rotate tool to rotate the merged object. When he did it the whole thing rotated fine. When i do it the merged object separates as if the sub-tools didn't merge properly.
Any help on this would be great as i cant figure out whats going wrong.

demigodssw

Maybe it has something to do with the auto masking. u cant try switching on/off the mask by polygroup and mask by topological option.
 
and try to add some screen shots of the mesh from next time.