Inconsistent Behaviour Double-Clicking a File to Import

Two different workstations:

-Workstation "A" - Double-Clicking a STEP or ParaSolid file begins the import process in the already-open Session of SolidWorks.

-Workstation "B" - Double-Clicking a STEP or ParaSolid file opens a new instance of SolidWorks.


Where is this behaviour set, and how can I get Workstation "B" to behave the same as Workstation "A"?