Global Selection
Each time you select components, you can decide whether you want to select from the current part or from the whole parts tree. Global selection allows you to select components from the whole parts tree:
• In the Select window, click Select, Global, and All.
If you do not click Global, Creo Elements/Direct 2D Access defaults to the current part.
1. Click 2D Access and then, in the Utilities group, click 
Delete.
Delete.2. In the Utilities group, click 
> 
Advanced.
> Advanced.The Select window opens.
Alternatively, press F2 to open the Select window.
3. Click Select, Global, All, Confirm and OK.
This command string deletes all components of the parts tree even if the active part is not the top part.
It should, however, be noted that even though all components (geometry, construction geometry, and text) contained within the parts tree will be deleted, it is not possible to delete the complete parts tree. The current part is never deleted and a path linkage to the top part is always maintained.