this function starts a drag session it should be called before any other Kinematic drag or Snapshot function is called. All subsequent functions will work with the Snapshots of the window assembly. All ProAsmcomppath should start from this assembly. All transforms belong to this assembly. The function can be called for design assemblies in Standard Assembly and Mechanism modes. It cannot be used if assembly is exploded, if sketcher is active, when component placement is active or when drag dialog is on screen.