diff --git a/src/simitembase.cpp b/src/simitembase.cpp
--- a/src/simitembase.cpp
+++ b/src/simitembase.cpp
@@ -26,6 +26,7 @@
 static const std::string _module_id("$Id$");
 
 SimItemBase::SimItemBase( void *v, QGraphicsScene *canvas ) {
+  canvas = NULL; // use assignment merely to obviate compilation warning
     obj=v;
 };
 
@@ -33,5 +34,5 @@ SimItemBase::~SimItemBase(void) {};
 
 
 void SimItemBase::userMove(double dx, double dy) {
-
+  dx = dy = 0.0; // use assignment merely to obviate compilation warning
 };