Freeze-after-Optimization

Steps to reproduce:
1. Add the following two parameter settings ("AddParameter()") to (any) trading strategy like so:
( I used "Gap Closer" )

CODE:
using WealthLab.Backtest;
using WealthLab.Core;
using System.Linq;

namespace WealthScript1 
{
   public class GapCloser : UserStrategyBase
   {
      public GapCloser() : base()
      {
         AddParameter("Entry Limit %", ParameterType.Double, 4.0, 0.5, 5.0, 0.1); // 0
         AddParameter("RSI Limit", ParameterType.Double, 50.0, 50.0, 100.0, 0.1); // 1
      }

      public override void Initialize(BarHistory bars)
      {
         gapSize = 2.5;
         longOnly = true;
         lastCompleteBar = bars.Count - 1;
         StartIndex = 1;
      }

      public override void Execute(BarHistory bars, int idx)
      {
         if (idx < lastCompleteBar)
         {
            openTradeBar = bars.Open[idx + 1];
            gapDown = bars.Low[idx] - openTradeBar;
            gapUp = openTradeBar - bars.High[idx];

            if (gapUp > gapSize) gapsUp++;
            if (gapDown > gapSize) gapsDown++;
         }
         else
         { 
            PlaceTrade(bars, TransactionType.Buy, OrderType.Limit, bars.Low[idx] - 0.01);
            PlaceTrade(bars, TransactionType.Short, OrderType.Limit, bars.High[idx] + 0.01);
         }            
         
         if (gapDown > gapSize)
            PlaceTrade(bars, TransactionType.Buy, OrderType.Limit, openTradeBar);
         if (gapUp > gapSize && !longOnly)
            PlaceTrade(bars, TransactionType.Short, OrderType.Limit, openTradeBar);

         foreach (Position openPos in OpenPositions)
            if (openPos != null)
               ClosePosition(openPos, OrderType.Limit, openPos.PositionType == PositionType.Long ? bars.Low[openPos.EntryBar - 1] : bars.High[openPos.EntryBar - 1]);

            if (idx == lastCompleteBar)
            {
               int closedGapsDown = GetPositions(false).Where(p => p.PositionType == PositionType.Long && !p.IsOpen).Count();
               int closedGapsUp = GetPositions(false).Where(p => p.PositionType == PositionType.Short && !p.IsOpen).Count();
               int gapsDown = GetPositions(false).Where(p => p.PositionType == PositionType.Long).Count();
               int gapsUp = GetPositions(false).Where(p => p.PositionType == PositionType.Short).Count();
               
               if ( gapsUp > 0)
                  DrawHeaderText(closedGapsUp + " Gaps Up Closed (" + (closedGapsUp * 100 / gapsUp) + "%)", WLColor.Red, 12);
               if ( gapsDown > 0)
                  DrawHeaderText( closedGapsDown + " Gaps Down Closed (" + (closedGapsDown * 100 / gapsDown) + "%)", WLColor.Green, 12);
            }
      }

      double gapUp, gapDown, gapSize, openTradeBar = 0;
      int lastCompleteBar, gapsUp, gapsDown;
      bool longOnly;
   }
}

2. Optimize both parameters with "Shrinking Window" (or any other optimizer)

3. At the end of optimization WL window becomes frozen

In Preferences->Backtest only "Metrics Report" is selected. (happens if only "Positions" is selected also)

Single Symbol Mode, Symbol "SPY" (happens for other symbols or Portfolio also)

Nothing unusual in Preferences->Backtest or Strategy Settings.