Thanks - I solved it in the end with this: (insert this indicator into a new blank pane)
a = 0;
Plot(a,"",colorWhite); // This creates enough chart space for the
rectangles
SetChartOptions(0,chartShowArrows|chartShowDates|chartWrapTitle);
Plot( C, "Close", ParamColor("Color", colorBlack ), styleNoTitle |
ParamStyle("Style") | GetPriceStyle() );
PlotShapes(shapeSquare,IIf(myVar==1,colorGreen,colorRed),0,0.5,0);
