[gui][roi] Use data from stack when applying roi

darfix/gui/roiSelectionWidget.py

@@ -161,7 +161,7 @@ class ROISelectionWidget(qt.QWidget):
         """
         self.roi = RectangleROI()
         self.roi.setGeometry(origin=self.getRoi().getOrigin(), size=self.getRoi().getSize())
-        frames = apply_3D_ROI(self.dataset.data, size=numpy.flip(self.roi.getSize()),
+        frames = apply_3D_ROI(self._sv.getStack()[0], size=numpy.flip(self.roi.getSize()),
                               center=numpy.flip(self.roi.getCenter()))
 
         self.setStack(frames)