Depending on when you told the debugger to start autostepping, you might've missed your chance to see the hash-marks on that block that you'll see when it's executing if you'd started the autostep before you got there. In other words, if you set a breakpoint on or before that OptoScript block, OR click Autostep BEFORE you click Run, you'll see the green pulsing outline around the block as it's running, possibly forever depending on the code.
But I'm guessing you want to see not just that the block is running, but what's going on in there...
You have a few options for ha, depending on the "bigger" problem you're trying to solve. Check out this post for some tips on debugging, including how you might pull that loop OUT of the OptoScript block, or set a break point inside that block.
Also keep in mind you "inspect" the conditions the While is looking for, or even add an index into that loop which gets incremented each time through the loop so you can see where you are in there. You could even add a string to your strategy that's just for status -- where you could add messages throughout the code to indicate where you are in the process.
I hope that helps!