improve DisplayParticle logic.

OTSIncAReportApp/2-CommonFunction/CommonClass/DisplayParticle.cs

@@ -810,6 +810,8 @@ namespace OTSIncAReportGraph
             rect.Width = i_width - rect.X ;
             rect.Height = i_height - rect.Y ;
 
+            if (rect.Width < 1) rect.Width = 1;
+            if (rect.Height < 1) rect.Height = 1;
         
 
             return rect;