diff --git a/GUI/Widgets/Fl_Canvas.C b/GUI/Widgets/Fl_Canvas.C
index 2fefa37..3cedb0e 100644
--- a/GUI/Widgets/Fl_Canvas.C
+++ b/GUI/Widgets/Fl_Canvas.C
@@ -582,17 +582,18 @@ istream &operator>>(istream &s, Fl_Canvas &o)
 			s>>NewWire.InputChild;
 			s>>NewWire.InputPort;	
 			s>>NewWire.InputTerminal;
-	
-			o.m_WireVec.push_back(NewWire);	
+			
+			// if we can turn on both ports
+			if (((Fl_DeviceGUI*)(o.child(NewWire.OutputChild)))->AddConnection(NewWire.OutputPort+
+					((Fl_DeviceGUI*)(o.child(NewWire.OutputChild)))->GetInfo()->NumInputs) &&
+				((Fl_DeviceGUI*)(o.child(NewWire.InputChild)))->AddConnection(NewWire.InputPort))
+			{
+				o.m_WireVec.push_back(NewWire);	
 
-			// Notify connection by callback
-			o.cb_Connection(&o,(void*)&NewWire);
-			o.m_Graph.AddConnection(NewWire.OutputID,NewWire.OutputTerminal,NewWire.InputID,NewWire.InputTerminal);
-				
-			// Turn on both ports
-			((Fl_DeviceGUI*)(o.child(NewWire.OutputChild)))->AddConnection(NewWire.OutputPort+
-				((Fl_DeviceGUI*)(o.child(NewWire.OutputChild)))->GetInfo()->NumInputs);
-			((Fl_DeviceGUI*)(o.child(NewWire.InputChild)))->AddConnection(NewWire.InputPort);
+				// Notify connection by callback
+				o.cb_Connection(&o,(void*)&NewWire);
+				o.m_Graph.AddConnection(NewWire.OutputID,NewWire.OutputTerminal,NewWire.InputID,NewWire.InputTerminal);
+			}				
 		}
 		
 	}
@@ -609,16 +610,17 @@ istream &operator>>(istream &s, Fl_Canvas &o)
 			s>>NewWire.InputChild;
 			s>>NewWire.InputPort;	
 	
-			o.m_WireVec.push_back(NewWire);	
+			// if we can turn on both ports
+			if (((Fl_DeviceGUI*)(o.child(NewWire.OutputChild)))->AddConnection(NewWire.OutputPort+
+					((Fl_DeviceGUI*)(o.child(NewWire.OutputChild)))->GetInfo()->NumInputs) &&
+				((Fl_DeviceGUI*)(o.child(NewWire.InputChild)))->AddConnection(NewWire.InputPort))
+			{
+				o.m_WireVec.push_back(NewWire);	
 
-			// Notify connection by callback
-			o.cb_Connection(&o,(void*)&NewWire);
-			o.m_Graph.AddConnection(NewWire.OutputID,false,NewWire.InputID,false);
-				
-			// Turn on both ports
-			((Fl_DeviceGUI*)(o.child(NewWire.OutputChild)))->AddConnection(NewWire.OutputPort+
-				((Fl_DeviceGUI*)(o.child(NewWire.OutputChild)))->GetInfo()->NumInputs);
-			((Fl_DeviceGUI*)(o.child(NewWire.InputChild)))->AddConnection(NewWire.InputPort);
+				// Notify connection by callback
+				o.cb_Connection(&o,(void*)&NewWire);
+				o.m_Graph.AddConnection(NewWire.OutputID,false,NewWire.InputID,false);
+			}					
 		}
 	}	
 	return s;
diff --git a/GUI/Widgets/Fl_DeviceGUI.C b/GUI/Widgets/Fl_DeviceGUI.C
index f4cffe3..23ac949 100644
--- a/GUI/Widgets/Fl_DeviceGUI.C
+++ b/GUI/Widgets/Fl_DeviceGUI.C
@@ -220,11 +220,16 @@ void Fl_DeviceGUI::Setup(const DeviceGUIInfo& Info, bool FirstTime)
 	}
 }
 
-void Fl_DeviceGUI::AddConnection(int n)  		 
+bool Fl_DeviceGUI::AddConnection(int n)  		 
 { 
-	m_PortVec[n]->Add();
-	m_PortVec[n]->value(1);
-	redraw();
+	if ( n < m_PortVec.size() ) 
+	{
+		m_PortVec[n]->Add();
+		m_PortVec[n]->value(1);
+		redraw();
+		return true;
+	}
+	return false;
 }
 	
 void Fl_DeviceGUI::RemoveConnection(int n)  		 
diff --git a/GUI/Widgets/Fl_DeviceGUI.h b/GUI/Widgets/Fl_DeviceGUI.h
index 729006e..32bf1ec 100644
--- a/GUI/Widgets/Fl_DeviceGUI.h
+++ b/GUI/Widgets/Fl_DeviceGUI.h
@@ -95,7 +95,7 @@ public:
 	
 	// aesthitic, to keep track of number of connections to know whether to 
 	// draw the port as occupied or not.
-	void          AddConnection(int n);
+	bool          AddConnection(int n);
 	void          RemoveConnection(int n);
 	
 	bool          GetPortValue(int n)            { return m_PortVec[n]->value(); }