diff --git a/BasePlugin/PluginFunctions.cc b/BasePlugin/PluginFunctions.cc
index 9c1c919b9f7c3e7dba89683d278313e2f23faf69..81a23204474af6708a900edad0619587b3526757 100644
--- a/BasePlugin/PluginFunctions.cc
+++ b/BasePlugin/PluginFunctions.cc
@@ -426,7 +426,7 @@ QPoint mapToLocal( const QPoint _point ) {
   return examiner_widgets_[activeExaminer_]->glMapFromGlobal(_point);
 }
 
-void setDrawMode( const ACG::SceneGraph::DrawModes::DrawMode _mode , int _viewer) {
+void setDrawMode( const ACG::SceneGraph::DrawModes::DrawMode _mode& , int _viewer) {
 
   if ( _viewer == ACTIVE_VIEWER )
     viewerProperties(activeExaminer()).drawMode(_mode);
diff --git a/BasePlugin/PluginFunctionsViewControls.hh b/BasePlugin/PluginFunctionsViewControls.hh
index 119fcce242fbc1fbd7d933f8d2db50b6eb7ea2ed..fad6b1a265a10dde0e1a16adb4e9384f55dda841 100644
--- a/BasePlugin/PluginFunctionsViewControls.hh
+++ b/BasePlugin/PluginFunctionsViewControls.hh
@@ -356,7 +356,7 @@ void perspectiveProjection( int _viewer = ALL_VIEWERS );
  * @param _mode New drawmode of the given viewer
  */
 DLLEXPORT
-void setDrawMode( const ACG::SceneGraph::DrawModes::DrawMode _mode , int _viewer = ALL_VIEWERS);
+void setDrawMode( const ACG::SceneGraph::DrawModes::DrawMode& _mode , int _viewer = ALL_VIEWERS);
 
 /** \brief Get the current draw Mode of a Viewer
  *