diff --git a/GraphX.Controls/Controls/GraphArea.cs b/GraphX.Controls/Controls/GraphArea.cs
index 6f97030..92bdfc0 100644
--- a/GraphX.Controls/Controls/GraphArea.cs
+++ b/GraphX.Controls/Controls/GraphArea.cs
@@ -616,7 +616,7 @@ namespace GraphX.Controls
             }
             catch (Exception ex)
             {
-                throw new GX_GeneralException(ex.Message + ". Probably you have an error in edge template.");
+                throw new GX_GeneralException(ex.Message + ". Probably you have an error in edge template.", ex);
             }
         }
 
diff --git a/GraphX.Controls/Controls/ZoomControl/ViewFinderDisplay.cs b/GraphX.Controls/Controls/ZoomControl/ViewFinderDisplay.cs
index 8cd0241..791e157 100644
--- a/GraphX.Controls/Controls/ZoomControl/ViewFinderDisplay.cs
+++ b/GraphX.Controls/Controls/ZoomControl/ViewFinderDisplay.cs
@@ -181,7 +181,7 @@ namespace GraphX.Controls
                 double aspectX = availableSize.Width/displayPanelSize.Width;
                 double aspectY = availableSize.Height/displayPanelSize.Height;
                 double scale = (aspectX < aspectY) ? aspectX : aspectY;
-                displayPanelSize = new Size(displayPanelSize.Width*scale, displayPanelSize.Height*scale);
+                displayPanelSize = new Size(Math.Max(0, displayPanelSize.Width * scale), Math.Max(0, displayPanelSize.Height * scale));
             }
 
             return displayPanelSize;
diff --git a/GraphX.Controls/Controls/ZoomControl/ZoomControl.cs b/GraphX.Controls/Controls/ZoomControl/ZoomControl.cs
index e0715a2..52784b7 100644
--- a/GraphX.Controls/Controls/ZoomControl/ZoomControl.cs
+++ b/GraphX.Controls/Controls/ZoomControl/ZoomControl.cs
@@ -594,7 +594,7 @@ namespace GraphX.Controls
                 // adjust the viewport from the coordinate space of the Content element
                 // to the coordinate space of the view finder display panel
                 var scale = _viewFinderDisplay.Scale;// *_viewboxFactor;
-                _viewFinderDisplay.ViewportRect = new Rect(viewport.Left * scale, viewport.Top * scale, viewport.Width * scale, viewport.Height * scale);
+                _viewFinderDisplay.ViewportRect = new Rect(viewport.Left * scale, viewport.Top * scale, Math.Max(0.0, viewport.Width * scale), Math.Max(0.0, viewport.Height * scale));
             }
         }
 
@@ -621,12 +621,12 @@ namespace GraphX.Controls
             if (viewFinderSize.Width > 0d && DoubleHelper.AreVirtuallyEqual(viewFinderSize.Height, 0d))
             {
                 // update height to accomodate width, while keeping a ratio equal to the actual content
-                viewFinderSize = new Size(viewFinderSize.Width, contentSize.Height * viewFinderSize.Width / contentSize.Width);
+                viewFinderSize = new Size(viewFinderSize.Width, Math.Max(0, contentSize.Height * viewFinderSize.Width / contentSize.Width));
             }
             else if (viewFinderSize.Height > 0d && DoubleHelper.AreVirtuallyEqual(viewFinderSize.Width, 0d))
             {
                 // update width to accomodate height, while keeping a ratio equal to the actual content
-                viewFinderSize = new Size(contentSize.Width * viewFinderSize.Height / contentSize.Height, viewFinderSize.Width);
+                viewFinderSize = new Size(Math.Max(0, contentSize.Width * viewFinderSize.Height / contentSize.Height), viewFinderSize.Width);
             }
 
             // determine the scale of the view finder display panel
@@ -642,7 +642,7 @@ namespace GraphX.Controls
 
             // set the ContentBounds and Scale properties on the view finder display panel
             _viewFinderDisplay.Scale = scale;
-            _viewFinderDisplay.ContentBounds = new Rect(new Size(vbWidth, vbHeight));
+            _viewFinderDisplay.ContentBounds = new Rect(new Size(Math.Max(0, vbWidth), Math.Max(0, vbHeight)));
         }
 
         private void UpdateViewboxFactor()
diff --git a/GraphX.PCL.Common/Exceptions/GX_GeneralException.cs b/GraphX.PCL.Common/Exceptions/GX_GeneralException.cs
index dc588f3..26c0fcc 100644
--- a/GraphX.PCL.Common/Exceptions/GX_GeneralException.cs
+++ b/GraphX.PCL.Common/Exceptions/GX_GeneralException.cs
@@ -8,5 +8,10 @@ namespace GraphX.PCL.Common.Exceptions
             : base(text)
         {
         }
-    }
+
+		public GX_GeneralException(string text, Exception innerException)
+			: base(text, innerException)
+		{
+		}
+	}
 }