[FIX] do not add ROI although button is pressed if ROIManager has no attached

fiber dataset. This should fix unwanted crashes.

src/gui/qt4/WMainWindow.cpp

@@ -558,6 +558,13 @@ void WMainWindow::slotActivateModule( QString module )
 
 void WMainWindow::newRoi()
 {
+    // do nothing if we can not get
+    if( !WKernel::getRunningKernel()->getRoiManager()->getDataSet() )
+    {
+        wlog::warn( "WMainWindow" ) << "Refused to add ROI, as ROIManager does not have data set associated.";
+        return;
+    }
+
     if ( m_datasetBrowser->getSelectedRoi().get() == NULL )
     {
         boost::shared_ptr< WROIBox > newRoi = boost::shared_ptr< WROIBox >( new WROIBox( wmath::WPosition( 60., 60., 60. ),

src/modules/fiberDisplay/WROIManagerFibers.cpp

@@ -101,6 +101,7 @@ void WROIManagerFibers::addFiberDataset( boost::shared_ptr< const WDataSetFibers
 
 void WROIManagerFibers::removeFiberDataset( boost::shared_ptr< const WDataSetFibers > /*fibers*/ )
 {
+    assert( 0 && "removeFiberDataset( --- ) not implemented yet." );
 }
 
 boost::shared_ptr< std::vector< bool > > WROIManagerFibers::getBitField()
@@ -147,6 +148,7 @@ void WROIManagerFibers::recalculate()
     {
         mbf = m_bitField;
     }
+
     int size = mbf->size();
     mbf->clear();