diff --git a/GUI/Model/Device/RectangularDetectorItem.cpp b/GUI/Model/Device/RectangularDetectorItem.cpp
index d92593d9728cd0bf5c03a1a51db9252e7609660e..6691cb79e09bf0bbc09a171bfbf4792bf6f9e0ea 100644
--- a/GUI/Model/Device/RectangularDetectorItem.cpp
+++ b/GUI/Model/Device/RectangularDetectorItem.cpp
@@ -68,6 +68,8 @@ RectangularDetectorItem::RectangularDetectorItem()
         "Resolution function", "Detector resolution function", "resolutionFunction",
         initResolutionFunction);
 
+    m_xSize = 100;
+    m_ySize = 100;
     m_width.init("Width (x-axis)", "Width of the detector", default_detector_width, "mm", 3,
                  RealLimits::positive(), "width");
     m_height.init("Height (y-axis)", "Height of the detector", default_detector_height, "mm", 3,
@@ -109,8 +111,10 @@ void RectangularDetectorItem::serialize(Serializer& s)
     s.rw(m_v0);
     s.rw(m_distance);
 
-    if (s.isReading())
+    if (s.isReading()) {
         setDetectorAlignment(static_cast<RectangularDetector::EDetectorArrangement>(alignment));
+        m_resolutionFunction->setUnit("mm");
+    }
 }
 
 void RectangularDetectorItem::setDetectorAlignment(
diff --git a/GUI/Model/Device/SphericalDetectorItem.cpp b/GUI/Model/Device/SphericalDetectorItem.cpp
index 5710e79eb33ce2487b898a1e9c981d02e2f8196a..28c1cf6e8bb7149eca29b842f6272aed0d388a80 100644
--- a/GUI/Model/Device/SphericalDetectorItem.cpp
+++ b/GUI/Model/Device/SphericalDetectorItem.cpp
@@ -51,6 +51,9 @@ void SphericalDetectorItem::serialize(Serializer& s)
     // own members
     s.rw("phiAxis", m_phiAxis);
     s.rw("alphaAxis", m_alphaAxis);
+
+    if (s.isReading())
+        m_resolutionFunction->setUnit(Unit::degree);
 }
 
 std::unique_ptr<IDetector2D> SphericalDetectorItem::createDomainDetector() const