Simulation speed slows when selecting Simulation tab

SKuhn

When simulating a flow in Palletizing Powerpac the speed of simulation is set for as fast as possible, which produces a very fast simulation. This is convenient to review the pallet and stack pattern to see if there are any issues with reach or collision with cell items. However, when the need to interrupt the flow by means of stopping cases the simulation tab is selected then the simulation speed is slowed down significantly. The only way to recover the simulation speed is to close RS and relaunch RS and Palletizing Powerpac. The GPU is running RS so performance settings shouldn't be an issue. 

Has anyone seen a significant drop is simulation speeds when selecting the simulation tab in RS?  Thanks in advance.