http://forum.kerbalspaceprogram.com/threads/38768-0-90-Editor-Extensions-v2-2-%28Bugfix-release%29-23-Dec?p=1624754&viewfull=1#post1624754

1. Vertical or horizontal snap a part
2. Select that part with the offset gizmo
3. Press space, which would normally revert all changes made by the gizmo
4. The part will jump to some location, possibly far away from your craft. Initially I thought it was being deleted